Troubleshooting Instructions for the 157-3210 Control Panel {1408, 7320} Caterpillar

Troubleshooting Instructions for the 157-3210 Control Panel {1408, 7320}

Usage:

315C AKE

Excavator:: 312C (S/N: CBA1-UP; BWH1-UP; BNN1-UP; DBN1-UP; FDS1-UP; CBT1-UP); 314C (S/N: KJA1-UP; PCA1-UP); 315C (S/N: CFB1-UP; CJC1-UP; AKE1-UP; ANF1-UP; CFT1-UP); 318C (S/N: FAA1-UP; GPA1-UP; BTG1-UP; DAH1-UP; MDY1-UP); 320C (S/N: APA1-UP; BEA1-UP; EGA1-UP; GHA1-UP; GLA1-UP; ANB1-UP; BCB1-UP; BDB1-UP; BGB1-UP; MAB1-UP; PAB1-UP; AMC1-UP; BDC1-UP; HBC1-UP; MAC1-UP; PAC1-UP; BDE1-UP; ALF1-UP; DBG1-UP; JTG1-UP; AKH1-UP; SAH1-UP; BKK1-UP; BBL1-UP; EGL1-UP; JPL1-UP; CLM1-UP; BCN1-UP; SBN1-UP; BER1-UP; BPR1-UP; TBR1-UP; RAW1-UP; ALX1-UP; BRX1-UP; CLZ1-UP); 321C (S/N: KBB1-UP; MCF1-UP; DAX1-UP); 322C (S/N: DAA1-UP; FED1-UP; BFK1-UP; BKM1-UP; BLP1-UP; BGR1-UP; EMR1-UP; MAR1-UP); 325C (S/N: CRB1-UP; JLC1-UP; BTD1-UP; JLD1-UP; DTF1-UP; AMH1-UP; CSJ1-UP; BMM1-UP; BKW1-UP); 330C (S/N: CYA1-UP; MCA1-UP; JAB1-UP; JCD1-UP; KDD1-UP; JNK1-UP; MKM1-UP; CAP1-UP; CGZ1-UP)

Introduction

This special instruction provides the information that is necessary to troubleshoot the 157-3210 Control Panel . A malfunction may occur with the control panel. The malfunction may be caused by faulty electrical connections to the control panel or by a faulty control panel. This special instruction is adaptable to the machines that are listed above.

Troubleshooting

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Personal injury can result from contact with refrigerant.
This system is under pressure at all times, even if the engine is not running. Heat should never be applied to a charged system.
Contact with refrigerant can cause frost bite. Keep face and hands away to help prevent injury.
Protective goggles must always be worn when refrigerant lines are opened, even if the gauges indicate the system is empty of refrigerant.
Always use caution when a fitting is removed. Slowly loosen the fitting. If the system is still under pressure, evacuate the system recovering the refrigerant before removing the fitting.
Personal injury or death can result from inhaling refrigerant through a lit cigarette.
Inhaling air conditioner refrigerant gas through a lit cigarette or other smoking method or inhaling fumes released from a flame contacting air conditioner refrigerant gas, can cause bodily harm or death.
Do not smoke when servicing air conditioners or wherever refrigerant gas may be present.

Before any checks of the air conditioning and heating system are made, move the machine to a smooth horizontal surface. Lower all implements to the ground. Make sure the transmission is in neutral or park and that the parking brake is engaged. Keep all other personnel away from the machine or where they can be seen.

Machine Preparation for Troubleshooting

Before any problem solving procedures are performed, read the manual for the heating and air conditioning system. Make a visual inspection of the complete air conditioning and heating system.

All charging and leak testing must be done in a ventilated area.
Avoid any physical contact with refrigerant. Contact can cause frostbite.
Always wear goggles when you are working on or testing any part of the air conditioning system.
Place a clean cloth over any valve or any connection that is opened.
Never weld any charged components.
Never solder any charged components.
Never steam clean any charged components.
Do not smoke when you recover the refrigerant or when you recycle the refrigerant.
Do not smoke when you charge the system.
Do not smoke when you perform a leak test on the system.
Do not smoke when you flush the system.
Do not leave refrigerant drums exposed to direct sunlight.
Do not carry refrigerant drums into the passenger compartment of the machine.
Dispose of any oil that is poly alkaline glycol (PAG) that has been opened but not used. The moisture will contaminate the unused oil and the air conditioning system.

General Troubleshooting Information

Low refrigerant charge will cause a loss of cooling ability and a loss of lubrication in the compressor, which will result in failure of the compressor.
Overcharge of refrigerant will cause a loss of cooling ability. A system that is overcharged will contain excess liquid refrigerant, which will severely damage the compressor. An overcharged system will fail two times faster than an undercharged system.
Too much oil in the system will contribute to a low refrigerant charge.
A small amount of moisture will penetrate the hoses that are used in R134a systems. Change the refrigerant dryer and the desiccant annually. Moisture causes sludge and moisture results in plugged systems.
Gauge readings for an undercharged R134a system may appear as symptoms of overcharge under certain conditions. This occurs when the ambient temperature is above 32 °C (90 °F) or in high humidity. Gauge readings that are Incorrect lead to a loss of cooling ability and failure of the compressor.
Refrigerant that is removed from a system cannot be weighed accurately. A 20% to 30% error can occur. The error is a result of oil that is removed from the system and a result of the inaccuracies of devices that are used for recovery.
Check the scale that is used for charging for accuracy after every 30 days or after every 30 uses.
After recovering a system, if the system pressure rises above 0 kPa (0 psi) within 5 minutes, the system must be recovered again until the pressure does not increase.
Frost can appear anywhere on a R134a air conditioning system. The appearance of frost does not always indicate a failure. In order to diagnose a blockage in the air conditioning system properly, the air temperature at the evaporator must be checked and pressure readings must be taken.
In order to check the function of the compressor, disconnect the hose from the inlet of the refrigerant dryer. Measure the pressure of suction of the compressor. The pressure should be a vacuum that is between 81 kPa (24 in Hg) to 95 kPa (28 in Hg). Do not operate the compressor for more than 2 minutes when the system pressure is below vacuum.
Perform regular maintenance on the refrigerant service units and change the oil in the vacuum pumps.
Secure lines and wires in order to prevent damage to the lines and wires.
The formation of black sludge deposits in the system is caused by the presence of moisture in R134a systems and by mixing charges of R134a and R12. The black sludge deposits can cause a blockage in the system.
The presence of white foam during recovery is normal. The foam is caused by the mixing of oil and refrigerant.
R134a system charges must be within 0.03 kg (1.000 oz) to .06 kg (2.000 oz) of the specified charge for the machine.
A drain line that is plugged or a drain line that is pinched may cause a backup of condensate and leakage into the cab.
Missing drain valves may cause a backup of condensate and leakage into the cab.
Missing drain valves will allow dust to be sucked into the evaporator coil and the heater coil.

A cab pressure of 0.05 kPa (0.200 inch of H₂O) to 0.15 kPa (0.600 inch of H₂O) and proper maintenance of the air conditioner filter will result in the following conditions:

Reduction of dust
Reduction of noise
More efficient HVAC performance

A loss of cooling ability of the system and failure of the compressor may be caused by one or more of the following conditions.

Low charge
Overcharge
Too much oil
Too little oil
Dirty filter or plugged filter
Dirty condenser or plugged condenser
Dirty evaporator or plugged evaporator
Dirty orifice tube or plugged orifice tube
Dirty expansion valve or plugged expansion valve
Too much moisture in the system
Missing drain valves for the evaporator

Visual Inspection

Before you conduct a performance check of the air conditioning system, the following items should be checked:

Check the condenser and the evaporator for any type of restriction that will obstruct air flow. Check for dirt, insects, plastic bags, etc.

Clean the fresh air filters and clean the recirculation filters.

Check for a loose belt on the compressor.

Check the moisture indicator on the receiver-dryer. If the indicator is pink or white, there is moisture in the system. Replace the receiver-dryer or the in-line dryer. Refer to Disassembly and Assembly, "Receiver (Refrigerant Dryer) Remove and Install" for instructions on replacing the receiver-dryer. If the moisture indicator is blue, the system is normal.

Check the drain tube on the evaporator. The drain tube should not be obstructed.

Inspecting the Wiring Harness

Make sure that the electrical connection between the control panel and the wiring harness is properly completed. If an error code is still displayed on the control panel, begin the fault diagnosis that follows.

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Illustration 1	g01177333
36-Pin Connector

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Table 1
Pinout Specifications for the Wiring Harness
Connector Pin	Function
1	Recirculation/Fresh Air Servo Potentiometer Signal
2	A/M Servo Potentiometer Signal
3	Servo Potentiometer Power
4	Refrigerant Dual Pressure Switch
5	Light Switch Signal
6	Power
7	None
8	BLC Control Signal
9	Discharge (1) Servo Potentiometer Signal
10	Discharge (2) Servo Potentiometer Signal
11	Discharge (3) Servo Potentiometer Signal
12	Recirculation Temperature Thermistor
13	Discharge Temperature Thermistor
14	Water Temperature Thermistor
15	Fresh Air Temperature Thermistor
16	Sunlight Sensor
17	Condenser Relay
18	Compressor Clutch Relay
19	Blower Motor (Main Relay)
20	A/M Servo (A) Terminal
21	A/M Servo (B) Terminal
22	Recirculation/Fresh Air Servo (B) Terminal
23	Recirculation/Fresh Air Servo (A) Terminal
24	Discharge (1) Servo (B) Terminal
25	Discharge (1) Servo (A) Terminal
26	Discharge (2) Servo (B) Terminal
27	Sensor Ground
28	Ground
29	None
30	None
31	None
32	None
33	None
34	Discharge (3) Servo (A) Terminal
35	Discharge (3) Servo (B) Terminal
36	Discharge (2) Servo (A) Terminal

Troubleshooting Faults With Service Codes

Starting the Fault Diagnosis

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Illustration 2	g01176017
Climate Control Panel with Air Conditioning (1) Temperature switch (increase) (2) LCD panel (3) Fan switch (increase) (4) Air inlet select switch (5) On/Off switch (6) Temperature switch (decrease) (7) Fan switch (decrease) (8) Defrost mode

Note: Understand the starting procedure before you begin.

Turn the engine start switch ON.

Turn On/Off switch (5) of the air conditioner OFF.

Depress the temperature switch (increase) (1) and the temperature switch (decrease) (6) on the control panel at the same time. Hold both switches down for at least three seconds.

The diagnosis procedure shall start. If any error is memorized, the smallest error code is displayed on LCD panel (2). If no problems exist, "E-.-" is displayed.

When the temperature switch (increase) (1) is depressed, error codes are displayed. The error codes are displayed in ascending order from "E11" to "E51". When the temperature switch (decrease) (6) is depressed, error codes are displayed. The error codes are displayed in descending order from "E51" to "E11".
Note: When only one error code exists, the same display is repeated. A flashing display means that the error code is continuing from the past. A non-flashing display means that the error code was found in the past, but the error code is not found now.

When the fault diagnosis is running, the control of each function is altered.
- All outputs from the control panel except error codes are turned OFF.
- The panel light turns ON.

Clear the error codes. Depress the following two switches on the control panel at the same time: air inlet select switch (4) and defrost mode (8). Hold both switches down for at least three seconds.
Note: Clear any error codes when the equivalent problems have been repaired. Make sure that the same error code is not displayed again. When a problem has not yet been repaired, the equivalent error code should be displayed again.

Ending the Fault Diagnosis

There are two ways to end the fault diagnosis.

Turn the engine start switch OFF.

Press power switch (5) .

English Versus Metric Toggle

In order to convert the temperature reading from Degrees Celsius to Degrees Fahrenheit, depress both of the fan speed switches at the same time for five seconds. The same action is used for converting the temperature reading from Degrees Fahrenheit to Degrees Celsius.

Automatic Operation of the Fan

When the climate control system is operating in the automatic mode, the fan may automatically start without any operation. This is caused by a temperature control system. The control panel operation is not faulty. When the coolant temperature is less than 25 °C (77 °F), a fan is stopped. When the coolant temperature is more than 25 °C (77 °F), a fan is started and maximum air flow is reached at 55 °C (131 °F).

Error Codes

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Table 2
Error Codes for the Automatic Temperature Control (ATC)
Code	Problem Area	Problem
"E-.-"	None	None
"E11"	Recirculation air sensor	Open circuit
"E12"	Recirculation air sensor	Short circuit
"E13"	Fresh air sensor	Open circuit
"E14"	Fresh air sensor	Short circuit
"E15"	Water temperature sensor	Open circuit
"E16"	Water temperature sensor	Short circuit
"E17"	Sunlight sensor	Open circuit
"E18"	Sunlight sensor	Short circuit
"E21"	Evaporator sensor	Open circuit
"E22"	Evaporator sensor	Short circuit
"E43"	Air damper (discharge air)	Incorrect movement
"E44"	Air damper (mixed air)	Incorrect movement
"E45"	Air damper (recirculated/fresh air)	Incorrect movement
"E51"	Refrigerant pressure switch	High/Low error

Air Conditioning E11 (Recirculation Sensor (Open Circuit))

ReferenceRefer to the Testing and Adjusting, "Air Conditioning System Schematic" section for the correct electrical schematic for your machine.

ReferenceRefer to the System Operations, "Air Conditioning System" section for the proper location of the recirculation air sensor for your machine.

Probable Causes

The recirculation air sensor has a open circuit.
The wiring harness that is connected to the control panel has an open circuit or the harness connector is disconnected.

Recirculation Air Sensor Check (Open Circuit)

Measure the value of the resistance in the recirculation air sensor. See ""Specifications" ". Proceed to Step 2.

If the resistance value is incorrect see Step 3. If the resistance value is correct see Step 4.

Replace the recirculation air sensor.

Disconnect the connectors from the sensor and measure the voltage between the connectors L GN/YL and GY/YL. See ""Specifications" ". Proceed to Step 5.

If the voltage value is incorrect see Step 6. If the voltage value is correct see Step 7.

Check the harness and repair the harness between the connector and the control unit. Also, check the system power source.

Fit the sensor and measure the voltage between terminals 12 and 27 of control unit. See ""Specifications" ". Proceed to Step 8.

If the voltage values are incorrect see Step 9. If the voltage values are correct see Step 10.

Check the harness and repair the harness between the connector and the control unit.

Replace the control unit.

Specifications

Resistance in the recirculation air sensor

0 °C (32 °F) ... 16 kΩ

25 °C (77 °F) ... 5 kΩ

Voltage between connectors ... 5.0 V

Voltage between terminals

10 °C (50 °F) ... 3.43 V

20 °C (68 °F) ... 2.87 V

25 °C (77 °F) ... 2.59 V

30 °C (86. °F) ... 2.32 V

Wiring Harness Connector Check (Open Circuit)

Electrical problems are often caused by faulty electrical wires that have either a open circuit or a short circuit. The following procedure explains the test for a open circuit.

Turn the battery disconnect switch key and the key start switch to the OFF position.
Note: A separate electrical wire must be used to perform an open circuit test. Any harness wire can be used.

Install a jumper (connecting wire) between the two electrical wires at one end of the harness.

Use a multimeter in order to check for continuity across the two electrical wires at the other end of the harness.

Turn the multimeter dial to the 200 ohm range and measure the electrical resistance.

Note: If there is continuity between the electrical wires, the multimeter will have a reading of less than 5 ohms. If there is not continuity, the electrical wire is faulty. The electrical wire should be replaced with another wire of the same gauge.

Air Conditioning E12 (Recirculation Air Sensor (Short Circuit))

ReferenceRefer to the Testing and Adjusting, "Air Conditioning System Schematic" section for the correct electrical schematic for your machine.

ReferenceRefer to the System Operations, "Air Conditioning System" section for the proper location of the recirculation air sensor for your machine.

Probable Causes

The recirculation air sensor has a short circuit.
The wiring harness that is connected to the control panel has a short circuit or the harness connector is disconnected.

Recirculation Air Sensor Check (Short Circuit)

Measure the value of the resistance in the recirculation air sensor. See ""Specifications" ". Proceed to Step 2.

If the resistance value is incorrect see Step 3. If the resistance value is correct see Step 4.

Replace the recirculation air sensor.

Disconnect the connectors from the sensor and measure the voltage between the connectors L GN/YL and GY/YL. See ""Specifications" ". Proceed to Step 5.

If the voltage value is incorrect see Step 6. If the voltage value is correct see Step 7.

Check the harness and repair the harness between the connector and the control unit. Also, check the system power source.

Fit the sensor and measure the voltage between terminals 12 and 27 of control unit. See ""Specifications" ". Proceed to Step 8.

If the voltage values are incorrect see Step 9. If the voltage values are correct see Step 10.

Check the harness and repair the harness between the connector and the control unit.

Replace the control unit.

Specifications

Resistance in the recirculation air sensor

0 °C (32 °F) ... 16 kΩ

25 °C (77 °F) ... 5 kΩ

Voltage between connectors ... 5.0 V

Voltage between terminals

10 °C (50 °F) ... 3.43 V

20 °C (68 °F) ... 2.87 V

25 °C (77 °F) ... 2.59 V

30 °C (86. °F) ... 2.32 V

Wiring Harness Connector Check (Short Circuit)

Electrical problems are often caused by faulty electrical wires that have either a open circuit or a short circuit. The following procedure explains the test for a short circuit.

Turn the battery disconnect switch key and the key start switch to the OFF position.

Disconnect the electrical wire.

Turn the multimeter dial to the 200 ohm range and measure the electrical resistance.

Use one multimeter probe in order to make contact with the connector of the faulty electrical wire.

Use the other probe from the multimeter to check for continuity across all other electrical wires in the same harness.

If there is continuity between any of the electrical wires, the multimeter will have a reading of less than 5 ohms.

Note: If there is not continuity, the electrical wire is faulty. The electrical wire should be replaced with another wire of the same gauge.

Air conditioning E13 (Fresh Air Sensor (Open Circuit))

ReferenceRefer to the Testing and Adjusting, "Air Conditioning System Schematic" section for the correct electrical schematic for your machine.

ReferenceRefer to the System Operations, "Air Conditioning System" section for the proper location of the fresh air sensor for your machine.

Probable Causes

The fresh air sensor has a open circuit.
The wiring harness that is connected to the control panel has a open circuit or the harness connector is disconnected.

Fresh Air Sensor Check (Open Circuit)

Measure the value of the resistance in the fresh air sensor. See ""Specifications" ". Proceed to Step 2.

If the resistance value is incorrect see Step 3. If the resistance value is correct see Step 4.

Replace the fresh air sensor.

Disconnect the connectors from the sensor and measure the voltage between the connectors L GN/YL and GY/YL. See ""Specifications" ". Proceed to Step 5.

If the voltage value is incorrect see Step 6. If the voltage value is correct see Step 7.

Check the harness and repair the harness between the connector and the control unit. Also, check the system power source.

Fit the sensor and measure the voltage between terminals 15 and 27 of control unit. See ""Specifications" ". Proceed to Step 8.

If the voltage values are incorrect see Step 9. If the voltage values are correct see Step 10.

Check the harness and repair the harness between the connector and the control unit.

Replace the control unit.

Specifications

Resistance in the fresh air sensor

0 °C (32 °F) ... 6 kΩ

25 °C (77 °F) ... 1.8 kΩ

Voltage between connectors ... 5.0 V

Voltage between terminals

10 °C (50 °F) ... 2.99 V

20 °C (68 °F) ... 2.45 V

25 °C (77 °F) ... 2.20 V

30 °C (86. °F) ... 1.96 V

Wiring Harness Connector Check (Open Circuit)

Electrical problems are often caused by faulty electrical wires that have either a open circuit or a short circuit. The following procedure explains the test for a open circuit.

Turn the battery disconnect switch key and the key start switch to the OFF position.
Note: A separate electrical wire must be used to perform an open circuit test. Any harness wire can be used.

Install a jumper (connecting wire) between the two electrical wires at one end of the harness.

Use a multimeter in order to check for continuity across the two electrical wires at the other end of the harness.

Turn the multimeter dial to the 200 ohm range and measure the electrical resistance.

Air Conditioning E14 (Fresh Air Sensor (Short Circuit))

ReferenceRefer to the Testing and Adjusting, "Air Conditioning System Schematic" section for the correct electrical schematic for your machine.

ReferenceRefer to the System Operations, "Air Conditioning System" section for the proper location of the fresh air sensor for your machine.

Probable Causes

The fresh air sensor has a short circuit.
The wiring harness that is connected to the control panel has a short circuit or the harness connector is disconnected.

Fresh Air Sensor Check (Short Circuit)

Measure the value of the resistance in the fresh air sensor. See ""Specifications" ". Proceed to Step 2.

If the resistance value is incorrect see Step 3. If the resistance value is correct see Step 4.

Replace the fresh air sensor.

Disconnect the connectors from the sensor and measure the voltage between the connectors L GN/YL and GY/YL. See ""Specifications" ". Proceed to Step 5.

If the voltage value is incorrect see Step 6. If the voltage value is correct see Step 7.

Check the harness and repair the harness between the connector and the control unit. Also, check the system power source.

Fit the sensor and measure the voltage between terminals 15 and 27 of control unit. See ""Specifications" ". Proceed to Step 8.

If the voltage values are incorrect see Step 9. If the voltage values are correct see Step 10.

Check the harness and repair the harness between the connector and the control unit.

Replace the control unit.

Specifications

Resistance in the fresh air sensor

0 °C (32 °F) ... 6 kΩ

25 °C (77 °F) ... 1.8 kΩ

Voltage between connectors ... 5.0 V

Voltage between terminals

10 °C (50 °F) ... 2.99 V

20 °C (68 °F) ... 2.45 V

25 °C (77 °F) ... 2.20 V

30 °C (86. °F) ... 1.96 V

Wiring Harness Connector Check (Short Circuit)

Electrical problems are often caused by faulty electrical wires that have either a open circuit or a short circuit. The following procedure explains the test for a short circuit.

Turn the battery disconnect switch key and the key start switch to the OFF position.

Disconnect the electrical wire.

Turn the multimeter dial to the 200 ohm range and measure the electrical resistance.

Use one multimeter probe in order to make contact with the connector of the faulty electrical wire.

Use the other probe from the multimeter to check for continuity across all other electrical wires in the same harness.

If there is continuity between any of the electrical wires, the multimeter will have a reading of less than 5 ohms.

Note: If there is not continuity, the electrical wire is faulty. The electrical wire should be replaced with another wire of the same gauge.

Air Conditioning E15 (Water Temperature Sensor (Open Circuit))

ReferenceRefer to the Testing and Adjusting, "Air Conditioning System Schematic" section for the correct electrical schematic for your machine.

ReferenceRefer to the System Operations, "Air Conditioning System" section for the proper location of the water temperature sensor for your machine.

Probable Causes

The water temperature sensor has a open circuit.
The wiring harness that is connected to the control panel has a open circuit or the harness connector is disconnected.

Water Temperature Sensor Check (Open Circuit)

Measure the value of the resistance in the water temperature sensor. See ""Specifications" ". Proceed to Step 2.

If the resistance value is incorrect see Step 3. If the resistance value is correct see Step 4.

Replace the water temperature sensor.

Disconnect the connectors from the sensor and measure the voltage between the connectors L GN/YL and BY. See ""Specifications" ". Proceed to Step 5.

If the voltage value is incorrect see Step 6. If the voltage value is correct see Step 7.

Check the harness and repair the harness between the connector and the control unit. Also, check the system power source.

Fit the sensor and measure the voltage between terminals 14 and 27 of control unit. See ""Specifications" ". Proceed to Step 8.

If the voltage values are incorrect see Step 9. If the voltage values are correct see Step 10.

Check the harness and repair the harness between the connector and the control unit.

Replace the control unit.

Specifications

Resistance in the water temperature sensor

25 °C (77 °F) ... 4.8 kΩ

100 °C (212 °F) ... 0.32 kΩ

Voltage between connectors ... 5.0 V

Voltage between terminals

10 °C (50 °F) ... 3.43 V

20 °C (68 °F) ... 2.88 V

25 °C (77 °F) ... 2.59 V

30 °C (86. °F) ... 2.32 V

Wiring Harness Connector Check (Open Circuit)

Electrical problems are often caused by faulty electrical wires that have either a open circuit or a short circuit. The following procedure explains the test for a open circuit.

Turn the battery disconnect switch key and the key start switch to the OFF position.
Note: A separate electrical wire must be used to perform an open circuit test. Any harness wire can be used.

Install a jumper (connecting wire) between the two electrical wires at one end of the harness.

Use a multimeter in order to check for continuity across the two electrical wires at the other end of the harness.

Turn the multimeter dial to the 200 ohm range and measure the electrical resistance.

Air Conditioning E16 (Water Temperature Sensor (Short Circuit))

ReferenceRefer to the Testing and Adjusting, "Air Conditioning System Schematic" section for the correct electrical schematic for your machine.

ReferenceRefer to the System Operations, "Air Conditioning System" section for the proper location of the water temperature sensor for your machine.

Probable Causes

The water temperature sensor has a short circuit.
The wiring harness that is connected to the control panel has a short circuit or the harness connector is disconnected.

Water Temperature Sensor Check (Short Circuit)

Measure the value of the resistance in the water temperature sensor. See ""Specifications" ". Proceed to Step 2.

If the resistance value is incorrect see Step 3. If the resistance value is correct see Step 4.

Replace the water temperature sensor.

Disconnect the connectors from the sensor and measure the voltage between the connectors L GN/YL and BY. See ""Specifications" ". Proceed to Step 5.

If the voltage value is incorrect see Step 6. If the voltage value is correct see Step 7.

Check the harness and repair the harness between the connector and the control unit. Also, check the system power source.

Fit the sensor and measure the voltage between terminals 14 and 27 of control unit. See ""Specifications" ". Proceed to Step 8.

If the voltage values are incorrect see Step 9. If the voltage values are correct see Step 10.

Check the harness and repair the harness between the connector and the control unit.

Replace the control unit.

Specifications

Resistance in the water temperature sensor

25 °C (77 °F) ... 4.8 kΩ

100 °C (212 °F) ... 0.32 kΩ

Voltage between connectors ... 5.0 V

Voltage between terminals

10 °C (50 °F) ... 3.43 V

20 °C (68 °F) ... 2.88 V

25 °C (77 °F) ... 2.59 V

30 °C (86. °F) ... 2.32 V

Wiring Harness Connector Check (Short Circuit)

Electrical problems are often caused by faulty electrical wires that have either a open circuit or a short circuit. The following procedure explains the test for a short circuit.

Turn the battery disconnect switch key and the key start switch to the OFF position.

Disconnect the electrical wire.

Turn the multimeter dial to the 200 ohm range and measure the electrical resistance.

Use one multimeter probe in order to make contact with the connector of the faulty electrical wire.

Use the other probe from the multimeter to check for continuity across all other electrical wires in the same harness.

If there is continuity between any of the electrical wires, the multimeter will have a reading of less than 5 ohms.

Note: If there is not continuity, the electrical wire is faulty. The electrical wire should be replaced with another wire of the same gauge.

Air Conditioning E17 (Sunlight Sensor (Open Circuit))

ReferenceRefer to the Testing and Adjusting, "Air Conditioning System Schematic" section for the correct electrical schematic for your machine.

ReferenceRefer to the System Operations, "Air Conditioning System" section for the proper location of the sunlight sensor for your machine.

Probable Causes

The sunlight sensor has a open circuit.
The wiring harness that is connected to the control panel has a open circuit or the harness connector is disconnected.

Sunlight Sensor Check (Open Circuit)

Measure the value of the resistance in the sunlight sensor. See ""Specifications" ". Proceed to Step 2.

If the resistance value is incorrect see Step 3. If the resistance value is correct see Step 4.

Replace the sunlight sensor.

Disconnect the connectors from the sensor and measure the voltage between the connectors L GN/YL and PG. See ""Specifications" ". Proceed to Step 5.

If the voltage value is incorrect see Step 6. If the voltage value is correct see Step 7.

Check the harness and repair the harness between the connector and the control unit. Also, check the system power source.

Fit the sensor and measure the voltage between terminals 3 and 16 of control unit. See ""Specifications" ". Proceed to Step 8.

If the voltage values are incorrect see Step 9. If the voltage values are correct see Step 10.

Check the harness and repair the harness between the connector and the control unit.

Replace the control unit.

Specifications

Correct voltage for the sunlight sensor

Voltage between terminals ... 0.4 V to 0.6 V

Wiring Harness Connector Check (Open Circuit)

Electrical problems are often caused by faulty electrical wires that have either a open circuit or a short circuit. The following procedure explains the test for a open circuit.

Turn the battery disconnect switch key and the key start switch to the OFF position.
Note: A separate electrical wire must be used to perform an open circuit test. Any harness wire can be used.

Install a jumper (connecting wire) between the two electrical wires at one end of the harness.

Use a multimeter in order to check for continuity across the two electrical wires at the other end of the harness.

Turn the multimeter dial to the 200 ohm range and measure the electrical resistance.

Air Conditioning E18 (Sunlight Sensor (Short Circuit))

ReferenceRefer to the Testing and Adjusting, "Air Conditioning System Schematic" section for the correct electrical schematic for your machine.

ReferenceRefer to the System Operations, "Air Conditioning System" section for the proper location of the sunlight sensor for your machine.

Probable Causes

The sunlight sensor has a short circuit.
The wiring harness that is connected to the control panel has a short circuit or the harness connector is disconnected.

Sunlight Sensor Check (Short Circuit)

Measure the value of the resistance in the sunlight sensor. See ""Specifications" ". Proceed to Step 2.

If the resistance value is incorrect see Step 3. If the resistance value is correct see Step 4.

Replace the sunlight sensor.

Disconnect the connectors from the sensor and measure the voltage between the connectors L GN/YL and PG. See ""Specifications" ". Proceed to Step 5.

If the voltage value is incorrect see Step 6. If the voltage value is correct see Step 7.

Check the harness and repair the harness between the connector and the control unit. Also, check the system power source.

Fit the sensor and measure the voltage between terminals 3 and 16 of control unit. See ""Specifications" ". Proceed to Step 8.

If the voltage values are incorrect see Step 9. If the voltage values are correct see Step 10.

Check the harness and repair the harness between the connector and the control unit.

Replace the control unit.

Specifications

Short circuit condition for the sunlight sensor

Voltage between terminals ... 0 V

Wiring Harness Connector Check (Short Circuit)

Electrical problems are often caused by faulty electrical wires that have either a open circuit or a short circuit. The following procedure explains the test for a short circuit.

Turn the battery disconnect switch key and the key start switch to the OFF position.

Disconnect the electrical wire.

Turn the multimeter dial to the 200 ohm range and measure the electrical resistance.

Use one multimeter probe in order to make contact with the connector of the faulty electrical wire.

Use the other probe from the multimeter to check for continuity across all other electrical wires in the same harness.

If there is continuity between any of the electrical wires, the multimeter will have a reading of less than 5 ohms.

Note: If there is not continuity, the electrical wire is faulty. The electrical wire should be replaced with another wire of the same gauge.

Air Conditioning E21 (Evaporator Sensor (Open Circuit))

ReferenceRefer to the Testing and Adjusting, "Air Conditioning System Schematic" section for the correct electrical schematic for your machine.

ReferenceRefer to the System Operations, "Air Conditioning System" section for the proper location of the evaporator sensor for your machine.

Probable Causes

The evaporator sensor has a open circuit.
The wiring harness that is connected to the control panel has a open circuit or the harness connector is disconnected.

Evaporator Sensor Check (Open Circuit)

Measure the value of the resistance in the evaporator sensor. See ""Specifications" ". Proceed to Step 2.

If the resistance value is incorrect see Step 3. If the resistance value is correct see Step 4.

Replace the evaporator sensor.

Disconnect the connectors from the sensor and measure the voltage between the connectors L GN/YL and PG. See ""Specifications" ". Proceed to Step 5.

If the voltage value is incorrect see Step 6. If the voltage value is correct see Step 7.

Check the harness and repair the harness between the connector and the control unit. Also, check the system power source.

Fit the sensor and measure the voltage between terminals 13 and 27 of control unit. See ""Specifications" ". Proceed to Step 8.

If the voltage values are incorrect see Step 9. If the voltage values are correct see Step 10.

Check the harness and repair the harness between the connector and the control unit.

Replace the control unit.

Specifications

Resistance in the water temperature sensor

0 °C (32 °F) ... 5 kΩ

25 °C (77 °F) ... 1.8 kΩ

Voltage between connectors ... 5.0 V

Voltage between terminals

10 °C (50 °F) ... 1.83 V

20 °C (68 °F) ... 1.34 V

25 °C (77 °F) ... 1.13 V

30 °C (86. °F) ... 0.96 V

Wiring Harness Connector Check (Open Circuit)

Electrical problems are often caused by faulty electrical wires that have either a open circuit or a short circuit. The following procedure explains the test for a open circuit.

Turn the battery disconnect switch key and the key start switch to the OFF position.
Note: A separate electrical wire must be used to perform an open circuit test. Any harness wire can be used.

Install a jumper (connecting wire) between the two electrical wires at one end of the harness.

Use a multimeter in order to check for continuity across the two electrical wires at the other end of the harness.

Turn the multimeter dial to the 200 ohm range and measure the electrical resistance.

Air Conditioning E22 (Evaporator Sensor (Short Circuit))

ReferenceRefer to the Testing and Adjusting, "Air Conditioning System Schematic" section for the correct electrical schematic for your machine.

ReferenceRefer to the System Operations, "Air Conditioning System" section for the proper location of the evaporator sensor for your machine.

Probable Causes

The evaporator sensor has a short circuit.
The wiring harness that is connected to the control panel has a short circuit or the harness connector is disconnected.

Evaporator Sensor Check (Short Circuit)

Measure the value of the resistance in the evaporator sensor. See ""Specifications" ". Proceed to Step 2.

If the resistance value is incorrect see Step 3. If the resistance value is correct see Step 4.

Replace the evaporator sensor.

Disconnect the connectors from the sensor and measure the voltage between the connectors L GN/YL and PG. See ""Specifications" ". Proceed to Step 5.

If the voltage value is incorrect see Step 6. If the voltage value is correct see Step 7.

Check the harness and repair the harness between the connector and the control unit. Also, check the system power source.

Fit the sensor and measure the voltage between terminals 13 and 27 of control unit. See ""Specifications" ". Proceed to Step 8.

If the voltage values are incorrect see Step 9. If the voltage values are correct see Step 10.

Check the harness and repair the harness between the connector and the control unit.

Replace the control unit.

Specifications

Resistance in the water temperature sensor

0 °C (32 °F) ... 5 kΩ

25 °C (77 °F) ... 1.8 kΩ

Voltage between connectors ... 5.0 V

Voltage between terminals

10 °C (50 °F) ... 1.83 V

20 °C (68 °F) ... 1.34 V

25 °C (77 °F) ... 1.13 V

30 °C (86. °F) ... 0.96 V

Wiring Harness Connector Check (Short Circuit)

Electrical problems are often caused by faulty electrical wires that have either a open circuit or a short circuit. The following procedure explains the test for a short circuit.

Turn the battery disconnect switch key and the key start switch to the OFF position.

Disconnect the electrical wire.

Turn the multimeter dial to the 200 ohm range and measure the electrical resistance.

Use one multimeter probe in order to make contact with the connector of the faulty electrical wire.

Use the other probe from the multimeter to check for continuity across all other electrical wires in the same harness.

If there is continuity between any of the electrical wires, the multimeter will have a reading of less than 5 ohms.

Note: If there is not continuity, the electrical wire is faulty. The electrical wire should be replaced with another wire of the same gauge.

Air Conditioning E43 (Air Damper (Discharge Air))

ReferenceRefer to the Testing and Adjusting, "Air Conditioning System Schematic" section for the correct electrical schematic for your machine.

ReferenceRefer to the System Operations, "Air Conditioning System" section for the proper location of the air damper for your machine.

Probable Causes

The servo motor is faulty.
Debris is obstructing operation of the damper.
There is a fault in the wiring harness or the harness connector is disconnected.

Air Damper Check

Measure the value of the resistance in the servo motor between L GN/YL and PU/YL. See ""Specifications" ". Proceed to Step 2.

If the resistance value is incorrect see Step 3. If the resistance value is correct see Step 4.

Replace the servo motor.

Disconnect the connectors from the servo motor and measure the voltage between the connectors PU/YL and L GN/YL. See ""Specifications" ". Proceed to Step 5.

If the voltage value is incorrect see Step 6. If the voltage value is correct see Step 7.

Check the harness and repair the harness between the connector and the control unit. Also, check the power source of the system.

Reconnect the servo motor to the harness. Measure the voltage at the connector of the control panel between terminal 27 and the corresponding discharge damper in Table 3. Refer to ""Specifications" ". Proceed to Step 8.

If the voltage values are incorrect see Step 9. If the voltage values are correct see Step 10.

Check the harness and repair the harness between the connector and the control unit.

Replace the control unit.

Specifications

Resistance ... 6 kΩ

Voltage between connectors ... 5.0 V

Show/hide table

Table 3
Voltage Specifications (Face 2 Mode) ⁽¹⁾
	Terminals at the Control Unit	Voltage
Discharge outlet changeover damper	9, 27	4.67 V
DEF changeover damper	10, 27	4.5 V
FACE changeover damper	11, 27	5.0 V

Show/hide table

^( 1 )

Face 2 Mode is the air outlet for Upper Body and Under Seat.

Wiring Harness Connector Check

Electrical problems are often caused by faulty electrical wires that have either a open circuit or a short circuit. The following procedure explains the test for a open or a short circuit.

Test for an open circuit

Turn the battery disconnect switch key and the key start switch to the OFF position.
Note: A separate electrical wire must be used to perform an open circuit test. Any harness wire can be used.

Install a jumper (connecting wire) between the two electrical wires at one end of the harness.

Use a multimeter in order to check for continuity across the two electrical wires at the other end of the harness.

Turn the multimeter dial to the 200 ohm range and measure the electrical resistance.

Test for an short circuit

Turn the battery disconnect switch key and the key start switch to the OFF position.

Disconnect the electrical wire.

Turn the multimeter dial to the 200 ohm range and measure the electrical resistance.

Use one multimeter probe in order to make contact with the connector of the faulty electrical wire.

Use the other probe from the multimeter to check for continuity across all other electrical wires in the same harness.

If there is continuity between any of the electrical wires, the multimeter will have a reading of less than 5 ohms.

Note: If there is not continuity, the electrical wire is faulty. The electrical wire should be replaced with another wire of the same gauge.

Air Conditioning E44 (Air Damper (Mixed Air))

ReferenceRefer to the Testing and Adjusting, "Air Conditioning System Schematic" section for the correct electrical schematic for your machine.

ReferenceRefer to the System Operations, "Air Conditioning System" section for the proper location of the air damper for your machine.

Probable Causes

The servo motor is faulty.
Debris is obstructing the operation of the damper.
There is a fault in the wiring harness or the harness connector is disconnected.

Air Damper Check

Measure the value of the resistance in the servo motor between L GN/YL and PU/YL. See ""Specifications" ". Proceed to Step 2.

If the resistance value is incorrect see Step 3. If the resistance value is correct see Step 4.

Replace the servo motor.

Disconnect the connectors from the servo motor and measure the voltage between the connectors PU/YL and L GN/YL. See ""Specifications" ". Proceed to Step 5.

If the voltage value is incorrect see Step 6. If the voltage value is correct see Step 7.

Check the harness and repair the harness between the connector and the control unit. Also, check the system power source.

Fit the servo motor and measure the voltage between terminals 2 - 27 of the control unit. Measure the value at the MAX COOL or MAX HOT position. See ""Specifications" ". Proceed to Step 8.

If the voltage values are incorrect see Step 9. If the voltage values are correct see Step 10.

Check the harness and repair the harness between the connector and the control unit.

Replace the control unit.

Specifications

Resistance MAX COOL position ... 1.2 kΩ

Resistance MAX HOT position ... 4.8 kΩ

Voltage between connectors ... 5.0 V

Voltage between terminals 2 - 27 ... 4.0 V

Wiring Harness Connector Check

Electrical problems are often caused by faulty electrical wires that have either a open circuit or a short circuit. The following procedure explains the test for a open or a short circuit.

Test for an open circuit

Turn the battery disconnect switch key and the key start switch to the OFF position.
Note: A separate electrical wire must be used to perform an open circuit test. Any harness wire can be used.

Install a jumper (connecting wire) between the two electrical wires at one end of the harness.

Use a multimeter in order to check for continuity across the two electrical wires at the other end of the harness.

Turn the multimeter dial to the 200 ohm range and measure the electrical resistance.

Test for an short circuit

Turn the battery disconnect switch key and the key start switch to the OFF position.

Disconnect the electrical wire.

Turn the multimeter dial to the 200 ohm range and measure the electrical resistance.

Use one multimeter probe in order to make contact with the connector of the faulty electrical wire.

Use the other probe from the multimeter to check for continuity across all other electrical wires in the same harness.

If there is continuity between any of the electrical wires, the multimeter will have a reading of less than 5 ohms.

Note: If there is not continuity, the electrical wire is faulty. The electrical wire should be replaced with another wire of the same gauge.

Air Conditioning E45 (Air Damper (Recirculation/Fresh Air))

ReferenceRefer to the Testing and Adjusting, "Air Conditioning System Schematic" section for the correct electrical schematic for your machine.

ReferenceRefer to the System Operations, "Air Conditioning System" section for the proper location of the air damper for your machine.

Probable Causes

The servo motor is faulty.
Debris is obstructing the operation of the damper.
There is a fault in the wiring harness or the harness connector is disconnected.

Air Damper Check

Measure the value of the resistance in the servo motor between L GN/YL and PU/YL. See ""Specifications" ". Proceed to Step 2.

If the resistance value is incorrect see Step 3. If the resistance value is correct see Step 4.

Replace the servo motor.

Disconnect the connectors from the servo motor and measure the voltage between the connectors PU/YL and L GN/YL. See ""Specifications" ". Proceed to Step 5.

If the voltage value is incorrect see Step 6. If the voltage value is correct see Step 7.

Check the harness and repair the harness between the connector and the control unit. Also, check the system power source.

Fit the servo motor and measure the voltage between terminals 1 - 27 of the control unit. Measure the value at the RECIRCULATION and FRESH AIR position. See ""Specifications" ". Proceed to Step 8.

If the voltage values are incorrect see Step 9. If the voltage values are correct see Step 10.

Check the harness and repair the harness between the connector and the control unit.

Replace the control unit.

Specifications

Resistance RECIRCULATION position ... 0.4 kΩ

Resistance FRESH AIR position ... 5.4 kΩ

Voltage between connectors ... 5.0 V

Voltage between terminals 1 - 27 ... 4.5 V

Wiring Harness Connector Check

Electrical problems are often caused by faulty electrical wires that have either a open circuit or a short circuit. The following procedure explains the test for a open or a short circuit.

Test for an open circuit

Turn the battery disconnect switch key and the key start switch to the OFF position.
Note: A separate electrical wire must be used to perform an open circuit test. Any harness wire can be used.

Install a jumper (connecting wire) between the two electrical wires at one end of the harness.

Use a multimeter in order to check for continuity across the two electrical wires at the other end of the harness.

Turn the multimeter dial to the 200 ohm range and measure the electrical resistance.

Test for an short circuit

Turn the battery disconnect switch key and the key start switch to the OFF position.

Disconnect the electrical wire.

Turn the multimeter dial to the 200 ohm range and measure the electrical resistance.

Use one multimeter probe in order to make contact with the connector of the faulty electrical wire.

Use the other probe from the multimeter to check for continuity across all other electrical wires in the same harness.

If there is continuity between any of the electrical wires, the multimeter will have a reading of less than 5 ohms.

Note: If there is not continuity, the electrical wire is faulty. The electrical wire should be replaced with another wire of the same gauge.

Air Conditioning E51 (Refrigerant Pressure Switch)

ReferenceRefer to the appropriate Testing and Adjusting, "Air Conditioning System Schematic" for the correct electrical schematic for your machine.

ReferenceRefer to the System Operations, "Air Conditioning System" section for the proper location of the refrigerant pressure switch for your machine.

The High Pressure Cutoff Switch is Activated

Causes

Poor cooling by the refrigerant condenser
Abnormally high ambient temperature
Overcharge of refrigerant
Air in the refrigerant

If the refrigerant condenser is not being cooled, the condenser could be clogged or the blower motor is not rotating. Make sure that the refrigerant condenser is clean and free of debris. Clean the condenser thoroughly with water. If the blower motor does not rotate, replace the blower motor or replace the relay.

An abnormally high ambient temperature can cause high pressure.

Check the system for an overcharge of refrigerant. If the system is overcharged with refrigerant, recover the refrigerant until the correct level is obtained.

If air is present in the refrigerant system, evacuate the refrigerant. Charge the system with refrigerant to the correct level.

The Low Pressure Cutoff Switch is Activated

Causes

Abnormally low ambient temperature
Insufficient refrigerant charge

An abnormally low ambient temperature can cause low pressure.

Check the system for a insufficient refrigerant charge. If the system is undercharged with refrigerant, recover the refrigerant until the correct level is obtained. Perform a leak test and charge the system to the correct level. Be sure to repair any leaks that are found before you charge the system.