R1700 Load Haul Dump Power Train, Steering, Braking, Hydraulic, and Machine Systems Caterpillar

Sensor Signal (Analog, Passive) - Test

Usage:

Implement ECM

The following is a list of Diagnostic Trouble Codes (DTCs) that are associated with the sensor signal (analog passive) circuits of the machine.

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Table 1
Implement ECM (MID 082)
DTC	Code Description	System Response
427-3	Front Axle Temperature Sensor: Voltage above normal	The transmission ECM compares the machine supply, 5 VDC component voltage, and the supply voltage for the specific sensor before issuing a fault.
427-4	Front Axle Temperature Sensor: Voltage below normal	The transmission ECM compares the machine supply, 5 VDC component voltage, and the supply voltage for the specific sensor before issuing a fault.
428-3	Rear Axle Temperature Sensor: Voltage above normal	The transmission ECM compares the machine supply, 5 VDC component voltage, and the supply voltage for the specific sensor before issuing a fault.
428-4	Rear Axle Temperature Sensor: Voltage below normal	The transmission ECM compares the machine supply, 5 VDC component voltage, and the supply voltage for the specific sensor before issuing a fault.
600-3	Hydraulic Oil Temperature Sensor: Voltage above normal	Hydraulic oil temperature will be unavailable. Calibrations and service tests cannot be initiated. This code is triggered when the system voltage is greater than 4.9 VDC.
600-4	Hydraulic Oil Temperature Sensor: Voltage below normal	Hydraulic oil temperature will be unavailable. Calibrations and service tests cannot be initiated. This code is triggered when the system voltage is greater than 0.2 VDC.

Possible causes for an FMI 3 Diagnostic code are:

The return circuit is open
The signal circuit is open or the sensor is disconnected
The signal circuit is shorted to another circuit
The sensor has failed
The ECM has failed. An ECM failure is unlikely

Possible causes for an FMI 4 Diagnostic code are:

The signal circuit for the sensor is shorted to ground
The sensor has failed
The ECM has failed. An ECM failure is unlikely

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Table 2
Temperature	Sensor Output Resistance (Ohms)
-25 °C (-13 °F)	13052.6
-20 °C (-4 °F)	9716.7
-15 °C (5 °F)	7302.3
-10 °C (14 °F)	5538.0
-5 °C (23 °F)	4236.7
0 °C (32 °F)	3268.3
5 °C (41 °F)	2541.5
10 °C (50 °F)	1991.4
15 °C (59 °F)	1571.9
20 °C (68 °F)	1249.5
25 °C (77 °F)	1000.0
30 °C (86 °F)	805.5
35 °C (95 °F)	652.8
40 °C (104 °F)	532.3

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Table 3
Temperature	Sensor Output Voltage (Volts)
−40° C (−40° F)	0.974
−35° C (−31° F)	0.966
−30° C (−22° F)	0.956
-25 °C (-13 °F)	0.944
-20 °C (-4 °F)	0.930
-15 °C (5 °F)	0.913
-10 °C (14 °F)	0.893
-5 °C (23 °F)	0.870
0 °C (32 °F)	0.844
5 °C (41 °F)	0.814
10 °C (50 °F)	0.781
15 °C (59 °F)	0.745
20 °C (68 °F)	0.707
25 °C (77 °F)	0.667
30 °C (86 °F)	0.626
35 °C (95 °F)	0.584
40 °C (104 °F)	0.541

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Illustration 1	g06160142
Schematic of the Implement ECM Analog Passive circuits

Possible causes for an FMI 3 Diagnostic code are:

The return circuit is open
The signal circuit is open or the sensor is disconnected
The signal circuit is shorted to another circuit
The sensor has failed
The ECM has failed. An ECM failure is unlikely

Possible causes for an FMI 4 Diagnostic code are:

The signal circuit for the sensor is shorted to ground
The sensor has failed
The ECM has failed. An ECM failure is unlikely

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Table 4
HVAC ECM (MID 087)
DTC	Code Description	System Response
2357-3	Air Conditioner Evaporator Coil Temperature Sensor: Voltage Above Normal	Air conditioning is disabled.
2357-4	Air Conditioner Evaporator Coil Temperature Sensor: Voltage Below Normal	Air conditioning is disabled.

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Illustration 2	g06256903
Schematic of the HVAC ECM Analog Passive circuits

Possible causes for an FMI 3 Diagnostic code are:

The return circuit is open
The signal circuit is open or the sensor is disconnected
The signal circuit is shorted to another circuit
The sensor has failed
The ECM has failed. An ECM failure is unlikely

Possible causes for an FMI 4 Diagnostic code are:

The signal circuit for the sensor is shorted to ground
The sensor has failed
The ECM has failed. An ECM failure is unlikely

Output resistance versus temperature for axle oil temperature sensors.

Output voltage ratio verse temperature for hydraulic oil temperature sensor .

Note: The diagram above is a simplified schematic of the connections for the sensor signal (analog passive) circuits. The schematic is electrically correct. However, not all the possible harness connectors are shown. Refer to the latest revision of the Electrical Schematic, UENR7282 for the complete schematic.

Diagnostic Code Troubleshooting Procedure

Note: Prior to beginning this procedure, inspect the harness connectors that are involved in this circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean, secure, and in good condition. If a problem with a connection is found, correct the problem and verify that the diagnostic code is active before performing a troubleshooting procedure.

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Table 5
Troubleshooting Test Steps	Values	Results
1. Identify The Active DTC Code Associated With The Suspect Circuit	Code present.	FMI 3 diagnostic code, proceed to Test Step 2. FMI 4 diagnostic code, proceed to Test Step 5.
Begin Process For FMI 3 Troubleshooting HERE
2. Check The Sensor Note: See Table 3 for a list of resistances related to specific temperature values. The maximum resistance for the sensor is 33,650 Ω, the minimum is 51.2 Ω. A. Turn the key start switch and the disconnect switch to the OFF position. B. Disconnect the sensor from the harness. C. Measure the resistance between pin 1 and 2 of the sensor.	The resistance reading agrees with the values from Table 3.	OK - The resistance reading agrees with the values in 3. Proceed to Test Step 3. NOT OK - The resistance reading does not agree with the values in 3. Repair: Replace the sensor. STOP
3. Check For An Open In The Sensor Circuit A. The key start switch and disconnect switch remain in the OFF position. B. The harness connector remains disconnected from the sensor. C. Disconnect the J1 and J2 connectors from the ECM. D. At the harness connector for the sensor install a jumper wire. E. At the harness connector for the ECM measure the resistance at the contacts for the sensor.	The resistance reading is less than 5 Ω.	OK - The resistance is less than 5 Ω. Proceed to Test Step 4. NOT OK - The resistance is greater than 5 Ω. Repair: Either the signal or the return circuit wire is open. Repair or replace the harness. STOP
4. Check The Signal Circuit For A Short. A. The disconnect switch and the key start switch remain in the OFF position. B. The harness connectors J1 and J2 remain disconnected from the ECM. C. Remove the jumper wire that was installed during the previous test step. D. At the ECM harness connectors measure the resistance between the positive connector and all J1 and J2 contacts.	Each resistance reading is greater than 5000 Ω.	OK - Each measurement is greater than 5000 Ω. Proceed to Test Step 7. NOT OK - A resistance measurement is less than 5000 Ω. Repair: A short exists between the signal circuit and the circuit with the low-resistance measurement. Repair or replace the machine harness.
Begin Process For FMI 4 Troubleshooting HERE
5. Check The Sensor A. Turn key start switch and disconnect switch ON. B. Ensure that the diagnostic code is active. C. Disconnect sensor from machine harness.	DTC is active.	OK - Diagnostic code remains active. Proceed to Test Step 6. NOT OK - Diagnostic code is no longer active. Repair: Replace the sensor. After sensor replacement, confirm that code is not active. STOP
6. Check The Wiring Harness Of The Sensor For A Short To Ground A. Turn the key start switch and the disconnect switch OFF. B. Disconnect machine harness connection at sensor. C. Disconnect machine harness connections at switch panel. D. At the machine harness connector for the switch panel, measure resistance from the signal contact of machine harness to all possible sources of ground. Measure resistance to all contacts of machine harness connectors for the monitor.	Each reading greater than 5K Ω.	OK - All resistance readings are greater than 5K Ω. Proceed to Test Step 7. NOT OK - One or more of the readings are less than 5 Ω. Repair: A short exists between the signal contact and the circuit with the low resistance. Repair or replace the machine harness. Note: A resistance that is greater than 5 Ω but less than 5K Ω would indicate a loose connection or a corroded connection in the circuit. A resistance measurement that is greater than 5K Ω would indicate an open in the circuit. STOP
7. Check If The Diagnostic Code Remains A. Turn the key start switch and the disconnect switch ON. B. Clear all diagnostic codes. C. Operate the machine. D. Stop the machine and engage safety lock lever. E. Check if diagnostic code for the sensor is active.	DTC Code is no longer active.	OK - Diagnostic code does not exist currently. Initial diagnostic code may have been caused by poor electrical connection or short at one of the harness connections. Resume machine operation. Repair: The initial diagnostic code was probably caused by a poor electrical connection or a short at one of the harness connectors. Resume normal machine operation. NOT OK - Diagnostic trouble code has not been corrected. Repair: If the diagnostic code has not been corrected after performing the procedure a second time, follow the procedure below for replacing the ECM. Prior to replacing the ECM, contact the Technical Communicator at your dealership for possible consultation with Caterpillar. This consultation may greatly reduce repair time. If the ECM requires replacement, refer to Troubleshooting, "ECM - Replace". STOP