C175 Oil&Gas Offshore Engine Caterpillar

DEF Tank Sensor - Test

Usage:

Use this procedure to troubleshoot a problem with the Diesel Exhaust Fluid (DEF) tank sensor. Also, use this procedure if one of the following diagnostic codes is active or easily repeated.

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Table 1
J1939 Code and Description	CDL Code and Description	Comments
4367-3 Aftertreatment #1 DEF Quick Thaw Tank Level : Voltage Above Normal	3131-3 Aftertreatment #1 DEF Tank #2 Level Sensor : Voltage Above Normal	The Electronic Control Module (ECM) detects signal voltage that is not in the acceptable range. The code is logged.
4367-4 Aftertreatment #1 DEF Quick Thaw Tank Level : Voltage Below Normal	3131-4 Aftertreatment #1 DEF Tank #2 Level Sensor : Voltage Below Normal	The ECM detects signal voltage that is not in the acceptable range. The code is logged.
4368-3 Aftertreatment #1 DEF Tank #2 Temperature : Voltage Above Normal	3135-3 Aftertreatment #1 DEF Tank #2 Temperature Sensor : Voltage Above Normal	The ECM detects signal voltage that is not in the acceptable range. The code is logged.
4368-4 Aftertreatment #1 DEF Tank #2 Temperature : Voltage Below Normal	3135-4 Aftertreatment #1 DEF Tank #2 Temperature Sensor : Voltage Below Normal	The ECM detects signal voltage that is not in the acceptable range. The code is logged.

The signal for the Diesel Exhaust Fluid (DEF) tank level sensor is routed to terminal 1 of the tank header unit. The signal for the DEF tank temperature sensor is routed to terminal 3 of the tank header unit. The sensor return is shared and is routed to terminal 2 of the tank header unit. The Electronic Control Module (ECM) provides short circuit protection for the internal power supply. A short circuit to the battery will not damage the internal power supply.

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Illustration 1	g06136353

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Table 2
Troubleshooting Test Steps	Values	Results
1. Check for Codes A. Turn the DC breaker to ON. B. Connect Cat^® Electronic Technician (ET) to the service tool connector. C. Determine if a code is active or logged.	Codes	Result: A -3 code is active. Proceed to Test Step 2. Result: A -4 code is active. Proceed to Test Step 3.
2. Create a Short at the Sensor Connector A. Verify that the wiring harness connector is free of debris, free of corrosion, and securely connected. B. Install a jumper wire between the appropriate signal and return wire at the sensor connector to create a short. C. Turn the DC breaker to ON. D. Connect Cat ET. E. Use Cat ET to monitor the following codes: - -4 code F. Turn the breaker to OFF.	Create a Short	Result: A -4 code becomes active. Repair: The wiring is OK. Replace the Diesel Exhaust Fluid (DEF) tank header assembly. Verify that the repair eliminated the problem. Result: A -4 code does not become active. Repair: Repair or replace the wiring harness. Verify that the repair eliminated the problem.
3. Create an Open at the Sensor Connector A. Disconnect the connector of the tank header unit. B. Turn the breaker to ON. C. Connect Cat ET. D. Use Cat ET to monitor the following codes: - -3 code D. Turn the breaker to OFF.	Create an Open	Result: A -3 code becomes active. Repair: The wiring is OK. Replace the DEF tank header assembly. Verify that the repair eliminated the problem. Result: A -3 code does not become active. Repair: Repair or replace the wiring harness. Verify that the repair eliminated the problem.

If the procedure did not correct the issue, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).