C2.2 Engines For Caterpillar Built Machines Caterpillar

Sensor Signal (Analog, Passive) - Test

Usage:

239D BL9

This procedure covers the following diagnostic codes:

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Table 1
Diagnostic Trouble Codes for Analog Passive Sensors
J1939 Code	Code Description	Comments
110-3	Engine Coolant Temperature : Voltage Above Normal	The ECM detects the following conditions: The signal voltage from the engine coolant temperature sensor is greater than 4.8 VDC for more than one second. An active diagnostic code will be generated. "Voltage Above Normal" will be displayed next to the status for "Engine Coolant Temperature" on the electronic service tool. The engine will be derated. The engine may show the following symptoms: Poor stability Poor cold running White smoke
110-4	Engine Coolant Temperature : Voltage Below Normal	The ECM detects the following conditions: The signal voltage from the engine coolant temperature sensor is less than 0.09 VDC for more than one second. An active diagnostic code will be generated. "Voltage Below Normal" will be displayed next to the status for "Engine Coolant Temperature" on the electronic service tool. The engine will be derated. The engine may show the following symptoms: Poor stability Poor cold running White smoke
172-3	Engine Air Inlet Temperature : Voltage Above Normal	The ECM detects the following conditions: The signal voltage from the air inlet temperature sensor is greater than 4.94 VDC for at least one second. The engine will be derated.
172-4	Engine Air Inlet Temperature : Voltage Below Normal	The ECM detects the following conditions: The signal voltage from the air inlet temperature sensor is less than 0.26 VDC for at least one second. The engine will be derated.
174-3	Engine Fuel Temperature 1 : Voltage Above Normal	The ECM detects the following conditions: The signal voltage from the fuel temperature sensor is greater than 4.8 VDC for more than one second. "Voltage Above Normal" will be displayed next to the status for "Engine Fuel Temperature" on the electronic service tool. The engine will be derated.
174-4	Engine Fuel Temperature 1 : Voltage Below Normal	The ECM detects the following conditions: The signal voltage from the fuel temperature sensor is less than 0.09 VDC for more than one second. "Voltage Below Normal" will be displayed next to the status for "Engine Fuel Temperature" on the electronic service tool. The engine will be derated.
4765-3	Aftertreatment #1 Diesel Oxidation Catalyst Intake Gas Temperature : Voltage Above Normal (If Equipped)	The ECM detects the following conditions: Coolant temperature is higher than 55° C (131° F). The signal voltage from the DOC inlet temperature sensor is greater than 4.92 VDC for more than 0.5 seconds. An active diagnostic code will be generated. "Voltage Above Normal" will be displayed next to the status for "DOC Inlet Temperature" on the electronic service tool. The engine will be derated.
4765-4	Aftertreatment #1 Diesel Oxidation Catalyst Intake Gas Temperature : Voltage Below Normal (If Equipped)	The ECM detects the following conditions: The signal voltage from the DOC inlet temperature sensor is less than 0.23 VDC for more than 0.5 seconds. An active diagnostic code will be generated. "Voltage Below Normal" will be displayed next to the status for "DOC Inlet Temperature" on the electronic service tool. The engine will be derated.
4766-3	Aftertreatment #1 Diesel Oxidation Catalyst Outlet Gas Temperature : Voltage Above Normal (If Equipped)	The ECM detects the following conditions: The signal voltage from the DOC inlet temperature sensor is greater than 4.92 VDC for more than 0.5 seconds. An active diagnostic code will be generated. "Voltage Above Normal" will be displayed next to the status for "DOC Inlet Temperature" on the electronic service tool. The engine will be derated.
4766-4	Aftertreatment #1 Diesel Oxidation Catalyst Outlet Gas Temperature : Voltage Below Normal (If Equipped)	The ECM detects the following conditions: The signal voltage from the DOC inlet temperature sensor is less than 0.23 VDC for more than 0.5 seconds. An active diagnostic code will be generated. "Voltage Below Normal" will be displayed next to the status for "DOC Inlet Temperature" on the electronic service tool. The engine will be derated.
Follow the troubleshooting procedure to identify the root cause of the fault.

No active 168 codes must exist before any of the above codes will become active.

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Illustration 1	g06088242
Schematic for the passive sensors

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Illustration 2	g03835279
Inlet manifold temperature sensor connector (1) Inlet manifold temperature signal (2) Sensor ground

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Illustration 3	g03835290
Coolant and fuel temperature sensor connector (1) Coolant temperature signal (2) Sensor ground

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Illustration 4	g03836008
DOC temperature sensor connector (if equipped) (1) Signal (2) Ground

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Table 2
Troubleshooting Test Steps	Values	Results
1. Check for Diagnostic Codes A. Establish communication between the electronic service tool and the ECM . Refer to Troubleshooting, "Electronic Service Tools", if necessary. B. Turn the keyswitch to the ON position. C. Look for a -3, or -4 active or logged code:	Diagnostic code	Result: A 110-X or 174-X diagnostic code is active. Proceed to Test Step 2. Result: A 172-X diagnostic code is active. Proceed to Test Step 3. Result: A 4765-X or 4766-X diagnostic code is active. Proceed to Test Step 4.
2. Check the Suspect Temperature Sensor A. Turn the keyswitch to the OFF position. B. Disconnect the harness connector from the suspect temperature sensor. C. Measure the resistance between pins 1 and 2 on the suspect sensor. Compare the results to Table 3.	0.2k Ohms to 3.0k Ohms	Result: The resistance measurement is outside limits. Repair: Install a replacement temperature sensor. Clear the diagnostic code and confirm that the fault has been eliminated. For an XXX-3 code, proceed to Test Step 5. For an XXX-4 code, proceed to Test Step 6.

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Table 3
Coolant Temperature	Sensor Resistance
20° C (68° F)	2.0k Ohms to 3.0k Ohms
40° C (104° F)	0.9k Ohms to 1.5k Ohms
60° C (140° F)	0.4k Ohms to 0.8k Ohms
80° C (176° F)	0.2k Ohms to 0.4k Ohms

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Table 4
Troubleshooting Test Steps	Values	Results
3. Check the Inlet Manifold Temperature Sensor A. Turn the keyswitch to the OFF position. B. Disconnect the harness connector from the inlet manifold temperature sensor. C. Measure the resistance between pins 1 and 2 on the inlet manifold temperature sensor. Compare the results to Table 5.	8k Ohms to 37k Ohms	Result: The resistance measurement is outside limits. Repair: Install a replacement inlet manifold temperature sensor. Clear the diagnostic code and confirm that the fault has been eliminated. Result: The resistance measurement is within limits. For an XXX-3 code, proceed to Test Step 5. For an XXX-4 code, proceed to Test Step 6.

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Table 5
Ambient Temperature	Sensor Resistance
0° C (32° F)	31k Ohms to 37k Ohms
20° C (68° F)	17k Ohms to 23k Ohms
60° C (140° F)	8k Ohms to 10k Ohms

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Table 6
Troubleshooting Test Steps	Values	Results
4. Check the Suspect DOC Temperature Sensor A. Turn the keyswitch to the OFF position. B. Disconnect the harness connector from the suspect DOC temperature sensor. C. Measure the resistance between pins 1 and 2 on the suspect DOC temperature sensor. Compare the results to Table 7.	8k Ohms to 37k Ohms	Result: The resistance measurement is outside limits. Repair: Install a replacement DOC temperature sensor. Clear the diagnostic code and confirm that the fault has been eliminated. Result: The resistance measurement is within limits. For an XXX-3 code, proceed to Test Step 5. For an XXX-4 code, proceed to Test Step 6.

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Table 7
Ambient Temperature	Sensor Resistance
0° C (32° F)	220k Ohms
20° C (68° F)	118k Ohms
40° C (104° F)	69k Ohms

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Table 8
Troubleshooting Test Steps	Values	Results
5. Check the Wiring between the Suspect Temperature Sensor and the ECM for an Open Circuit Refer to Illustration 1. A. Turn the keyswitch to the OFF position. B. Disconnect the harness connector from the suspect temperature sensor. C. Disconnect the engine interface connector. D. Disconnect the P1 and P2 connectors from the ECM, as applicable. E. Measure the resistance between the following pairs of pins: · Pin 1 on the suspect sensor harness connector and the applicable pin on the engine interface connector. · Pin 2 on the suspect sensor harness connector and the applicable pin on the engine interface connector. · The applicable pins on the engine interface connector and the associated pins on the P1 or P2 ECM connector. F. Reconnect the harness connector to the temperature sensor. G. Reconnect the engine interface connector. H. Reconnect the P1 and P2 connectors to the ECM.	Less than 2.0 Ohms	Result: One of the resistance measurements is more than 2.0 Ohms. Repair: Repair or replace the wiring harness. Clear the diagnostic code and confirm that the fault has been eliminated. Result: All the resistance measurements are less than 2.0 Ohms. Contact the Dealer Solutions Network (DSN).
6. Check the Wiring between the Suspect Temperature Sensor and the ECM for a Short Circuit A. Turn the keyswitch to the OFF position. B. Disconnect the harness connector from the suspect temperature sensor. C. Disconnect the engine interface connector. D. Disconnect the P1 and P2 connectors from the ECM, as applicable. E. Measure the resistance between pin 1 on the sensor harness connector and the other pins on the sensor side of the engine interface connector. Refer to Illustration 1. F. Measure the resistance between pin 2 on the sensor harness connector and the other pins on the sensor side of the engine interface connector. Refer to Illustration 1. G. Measure the resistance between the associated pins on the ECM side of the engine interface connector and the other pins on the engine interface connector. Refer to Illustration 1. H. Reconnect the harness connector to the suspect temperature sensor. I. Reconnect the engine interface connector. J. Reconnect the P1 and P2 connectors to the ECM, as applicable.	1.0k Ohm	Result: One of the resistance measurements is less than 1.0k Ohms. Repair: Repair or replace the wiring harness. Clear the diagnostic code and confirm that the fault has been eliminated. Result: All the resistance measurements are more than 1.0k Ohms. Contact the Dealer Solutions Network (DSN).