C175 Tier 4 Final Engines for Off-Highway Trucks Caterpillar

Use this procedure to troubleshoot a problem with a solenoid valve. Also, use this procedure if one of the following diagnostic codes is active or easily repeated.

Table 1

J1939 Code and Description	CDL Code and Description	Comments
3363-5 Aftertreatment #1 DEF Tank Heater : Current Below Normal	3126-5 Aftertreatment #1 DEF Tank #1 Heater Coolant Diverter Solenoid : Current Below Normal	This code indicates that there is a problem with the Aftertreatment #1 coolant diverter valve #1 and/or the electrical circuit for the coolant diverter valve.
3363-6 Aftertreatment #1 DEF Tank Heater : Current Above Normal	3126-6 Aftertreatment #1 DEF Tank #1 Heater Coolant Diverter Solenoid : Current Above Normal	This code indicates that there is a problem with the Aftertreatment #1 coolant diverter valve #1 and/or the electrical circuit for the coolant diverter valve.
4431–5 Aftertreatment #2 DEF Tank Heater : Current Below Normal	3128–5 Aftertreatment #2 DEF Tank #1 Heater Coolant Diverter Solenoid : Current Below Normal	This code indicates that there is a problem with the Aftertreatment #2 coolant diverter valve #1 and/or the electrical circuit for the coolant diverter valve.
4431–6 Aftertreatment #2 DEF Tank Heater : Current Above Normal	3128–6 Aftertreatment #2 DEF Tank #1 Heater Coolant Diverter Solenoid : Current Above Normal	This code indicates that there is a problem with the Aftertreatment #2 coolant diverter valve #1 and/or the electrical circuit for the coolant diverter valve.
5394-5 Aftertreatment DEF Dosing Valve : Current Below Normal	3821-5 Aftertreatment #1 DEF Dosing Valve Actuator : Current Below Normal	This code indicates that there is a problem with the Aftertreatment #1 Diesel Exhaust Fluid (DEF) injector #1 and/or the electrical circuit for the DEF injector.
5394-6 Aftertreatment DEF Dosing Valve : Current Above Normal	3821-6 Aftertreatment #1 DEF Dosing Valve Actuator : Current Above Normal	This code indicates that there is a problem with the Aftertreatment #1 DEF injector# 1 and/or the electrical circuit for the DEF injector.
5965-5 Aftertreatment #1 DEF Control Module Relay Control : Current Below Normal	3838-5 Aftertreatment #1 DEF Dosing Control Module Relay : Current Below Normal	This code indicates that there is a problem with the Pump Electronic Tank Unit (PETU) main power relay circuit or the PETU main power relay.
5965-6 Aftertreatment #1 DEF Control Module Relay Control : Current Above Normal	3838-6 Aftertreatment #1 DEF Dosing Control Module Relay : Current Above Normal	This code indicates that there is a problem with the PETU main power relay circuit or the PETU main power relay.
5974–5 Aftertreatment #2 DEF Dosing Valve #1 : Current Below Normal	5020–5 Aftertreatment #2 DEF Dosing Valve #1 : Current Below Normal	This code indicates that there is a problem with the Aftertreatment #2 DEF injector #1 and/or the electrical circuit for the DEF injector.
5974–6 Aftertreatment #2 DEF Dosing Valve #1 : Current Above Normal	5020–6 Aftertreatment #2 DEF Dosing Valve #1 : Current Above Normal	This code indicates that there is a problem with the Aftertreatment #2 DEF injector #1 and/or the electrical circuit for the DEF injector.
6324-5 Aftertreatment #1 DEF Dosing Valve #2 : Current Below Normal	5017-5 Aftertreatment #1 DEF Dosing Valve Actuator #2 : Current Below Normal	This code indicates that there is a problem with the Aftertreatment #1 DEF injector #2 and/or the electrical circuit for the DEF injector.
6324-6 Aftertreatment #1 DEF Dosing Valve #2 : Current Above Normal	5017-6 Aftertreatment #1 DEF Dosing Valve Actuator #2 : Current Above Normal	This code indicates that there is a problem with the Aftertreatment #1 DEF injector#2 and/or the electrical circuit for the DEF injector.
6325–5 Aftertreatment #2 DEF Dosing Valve #2 : Current Below Normal	5021–5 Aftertreatment #2 DEF Dosing Valve #2 : Current Below Normal	This code indicates that there is a problem with the Aftertreatment #2 DEF injector #2 and/or the electrical circuit for the DEF injector.
6325–6 Aftertreatment #2 DEF Dosing Valve #2 : Current Above Normal	5021–6 Aftertreatment #2 DEF Dosing Valve #2 : Current Above Normal	This code indicates that there is a problem with the Aftertreatment #2 DEF injector #2 and/or the electrical circuit for the DEF injector.
7488-5 Aftertreatment #1 DEF Dosing Valve #3 : Current Below Normal	5018-5 Aftertreatment #1 DEF Dosing Valve Actuator #3 : Current Below Normal	This code indicates that there is a problem with the Aftertreatment #1 DEF injector #3 and/or the electrical circuit for the DEF injector.
7488-6 Aftertreatment #1 DEF Dosing Valve #3 : Current Above Normal	5018-6 Aftertreatment #1 DEF Dosing Valve Actuator #3 : Current Above Normal	This code indicates that there is a problem with the Aftertreatment #1 DEF injector #3 and/or the electrical circuit for the DEF injector.
7489–5 Aftertreatment #2 DEF Dosing Unit #3 : Current Below Normal	5022–5 Aftertreatment #2 DEF Dosing Unit #3 : Current Below Normal	This code indicates that there is a problem with the Aftertreatment #2 DEF injector #3 and/or the electrical circuit for the DEF injector.
7489–6 Aftertreatment #2 DEF Dosing Unit #3 : Current Above Normal	5022–6 Aftertreatment #2 DEF Dosing Unit #3 : Current Above Normal	This code indicates that there is a problem with the Aftertreatment #2 DEF injector #3 and/or the electrical circuit for the DEF injector.
7546-5 Aftertreatment #1 DEF Dosing Valve #4 : Current Below Normal	5019-5 Aftertreatment #1 DEF Dosing Valve Actuator #4 : Current Below Normal	This code indicates that there is a problem with the Aftertreatment #1 DEF injector #4 and/or the electrical circuit for the DEF injector.
7546-6 Aftertreatment #1 DEF Dosing Valve #4 : Current Above Normal	5019-6 Aftertreatment #1 DEF Dosing Valve Actuator #4 : Current Above Normal	This code indicates that there is a problem with the Aftertreatment #1 DEF injector #4 and/or the electrical circuit for the DEF injector.
7547–5 Aftertreatment #2 DEF Dosing Valve #4 : Current Below Normal	5023–5 Aftertreatment #2 DEF Dosing Valve #4 : Current Below Normal	This code indicates that there is a problem with the Aftertreatment #2 DEF injector #4 and/or the electrical circuit for the DEF injector.
7547–6 Aftertreatment #2 DEF Dosing Valve #4 : Current Above Normal	5023–6 Aftertreatment #2 DEF Dosing Valve #4 : Current Above Normal	This code indicates that there is a problem with the Aftertreatment #2 DEF injector #4 and/or the electrical circuit for the DEF injector.
7573-5 Aftertreatment #1 DEF Tank Heater #2 : Current Below Normal	5011-5 Aftertreatment #1 DEF Tank Heater #2 : Current Above Normal	This code indicates that there is a problem with the Aftertreatment #1 coolant diverter valve #2 and/or the electrical circuit for the coolant diverter valve.
7573-6 Aftertreatment #1 DEF Tank Heater #2 : Current Above Normal	5011-6 Aftertreatment #1 DEF Tank Heater #2 : Current Below Normal	This code indicates that there is a problem with the Aftertreatment #1 coolant diverter valve #2 and/or the electrical circuit for the coolant diverter valve.
7575–5 Aftertreatment #2 DEF Tank Heater #2 : Current Below Normal	5012–5 Aftertreatment #2 DEF Tank Heater #2 : Current Below Normal	This code indicates that there is a problem with the Aftertreatment #2 coolant diverter valve #2 and/or the electrical circuit for the coolant diverter valve.
7575–6 Aftertreatment #2 DEF Tank Heater #2 : Current Above Normal	5012–6 Aftertreatment #2 DEF Tank Heater #2 : Current Above Normal	This code indicates that there is a problem with the Aftertreatment #2 coolant diverter valve #2 and/or the electrical circuit for the coolant diverter valve.

Electrical Checkouts on the Cat^® Electronic Technician (ET)

Table 2

Component	Controller	Electrical Checkout
DEF Injector	Diesel Exhaust Fluid Controller (DCU)	Aftertreatment #1 DEF Dosing System Prime Test: Initiate the appropriate Aftertreatment #1 DEF Dosing System Prime Test through Cat ET to activate the injector circuit.
Coolant Diverter Valve	Diesel Exhaust Fluid Controller (DCU)	DEF Coolant Diverter Valve Solenoid Override : Turn the keyswitch to the OFF position for 2 minutes. The keyswitch must be off for 2 minutes to allow the DEF pump to purge, to reset the code, and to reset the DCU. Turn the keyswitch to ON. Initiate the appropriate DEF Coolant Diverter Valve Solenoid Override through CAT ET to activate the coolant diverter valve circuit.
PETU Main Power Relay	A5:E2 Selective Catalyst Reduction Controller	Turn the keyswitch to OFF for 2 minutes. The keyswitch must be off for 2 minutes to allow the DEF pump to purge, to reset the code, and to reset the DCU. Turn the keyswitch to ON. Check for an active code.

Table 3

Required Tools		Qty
372-5260	Test Kit	1

Illustration 1	g06108244

Illustration 2	g06105509

Illustration 3	g06100050
The DEF pumps are on the front side of the Pump Electronic Tank Unit (PETU). (1) Aftertreatment #1 DEF Pump #1 (2) Aftertreatment #1 DEF Pump #2 (3) Aftertreatment #2 DEF Pump #1 (4) Aftertreatment #2 DEF Pump #2 (5) Coolant diverter valve for Aftertreatment #1 DEF Pump #1 (6) Coolant diverter valve for Aftertreatment #1 DEF Pump #2 (7) Coolant diverter valve for Aftertreatment #2 DEF Pump #1 (8) Coolant diverter valve for Aftertreatment #2 DEF Pump #2 (9) Aftertreatment #1 DEF Pump #1 header (10) Aftertreatment #1 DEF Pump #2 header (11) Aftertreatment #2 DEF Pump #1 header (12) Aftertreatment #2 DEF Pump #2 header (13) Aftertreatment #1 DEF Pump #1 backflow valve (14) Aftertreatment #1 DEF Pump #2 backflow valve (15) Aftertreatment #2 DEF Pump #1 backflow valve (16) Aftertreatment #2 DEF Pump #2 backflow valve (17) Aftertreatment #1 DEF Pump #1 electrical connection for DEF header (18) Aftertreatment #1 DEF Pump #2 electrical connection for DEF header (19) Aftertreatment #2 DEF Pump #1 electrical connection for DEF header (20) Aftertreatment #2 DEF Pump #2 electrical connection for DEF header

Illustration 4	g06105537
The DEF injectors are on the inlet of the Clean Emissions Module (CEM). There are injectors on both inlets of the dual CEM applications. (21) DEF injector 2 (Aftertreatment 1 DEF pump 1) (22) DEF injector 3 (Aftertreatment 1 DEF pump 1) (23) DEF injector 1 (Aftertreatment 1 DEF pump 2) (24) DEF injector 4 (Aftertreatment 1 DEF pump 2) (25) DEF injector 2 (Aftertreatment 2 DEF pump 1) (26) DEF injector 3 (Aftertreatment 2 DEF pump 1) (27) DEF injector 1 (Aftertreatment 2 DEF pump 2) (28) DEF injector 4 (Aftertreatment 2 DEF pump 2)

Probable Causes

• Codes

• Open circuit

• Short circuit

• Injectors

Recommended Actions

Reference: Refer to Troubleshooting, System Overview (Aftertreatment Identification) for locating aftertreatment components if necessary.

Table 4

Troubleshooting Test Steps	Values	Results
1. Check for Codes A. Connect Cat® Electronic Technician (ET) to the service tool connector. B. Determine if a code is active or logged.	Codes	Result : A -5 or -6 code related to the aftertreatment diesel exhaust fluid dosing valve (DEF Injector) is active or logged. Proceed to Test Step 4. Result : A -5code that is not related to the aftertreatment diesel exhaust fluid dosing valve (DEF Injector) is active or logged. Proceed to Test Step 2. Result : A -6 code that is not related to the aftertreatment diesel exhaust fluid dosing valve (DEF Injector) is active or logged. Proceed to Test Step 3.
2. Check the Wiring for an Open Circuit A. Verify that the harness connector is free of debris, free of corrosion and securely connected. B. Disconnect the solenoid from the harness. C. Connect a jumper wire between the terminals of the harness connector for the affected coil. The coil is replaced with a short circuit.	Create a Short	Result: A -5 code became active during the electrical checkout. The ECM did not detect the jumper wire. There is an open circuit in the wiring between the coil and the ECM connector. There may be a problem with a connector. Repair: Repair or replace the connectors or the wiring. Verify that the repair eliminated the problem. Result: A -6 code is activated during the electrical checkout. The ECM detected the jumper wire. There is a problem with the solenoid. Repair: Replace the solenoid. Verify that the repair eliminated the problem.
3. Check the Wiring for a Short Circuit A. Disconnect the solenoid from the harness.	Create an Open	Result: A -6 code became active during the electrical checkout. The ECM did not detect the open circuit. There is a short circuit in the wiring between the coil and the ECM connector. There may be a problem with a connector. Repair: Repair or replace the connectors or the wiring. Turn the keyswitch to OFF for 2 minutes. The keyswitch must be off for 2 minutes to allow the DEF pump to purge, the code to reset, and the DCU to reset. Verify that the repair eliminated the problem. Result: A -5 code is activated during the electrical checkout. The ECM detected the open circuit. There is a problem with the solenoid. Repair: Replace the solenoid. Turn the keyswitch to OFF for 2 minutes. The keyswitch must be off for 2 minutes to allow the DEF pump to purge, the code to reset, and the DCU to reset. Verify that the repair eliminated the problem.
4. Measure the Resistance of the Injector Note: A 372-5260 Test Kit is required for completing this procedure. A. Turn the keyswitch to OFF. Allow 2 minutes to elapse before proceeding. B. Disconnect the DEF injector from the applicable harness. C. Inspect the connector for damage or debris. D. Connect two 398-4987 Break-out Connectors to the DEF injector. The connectors must be used to prevent damage to the DEF injector connector. E. Measure the resistance of the DEF injector. Note: The resistance of the DEF injector should be in the range of 10 Ohms to 14 Ohms.	Ohms	Result: The resistance of the injector measured between 10 Ohms to 14 Ohms. Proceed to Test Step 5. Result: The resistance of the injector did not measure between 10 Ohms to 14 Ohms. A failed DEF injector has been detected. Repair: Replace the injector. Refer to the Disassembly and Assembly manual for additional information. Perform a "Aftertreatment #1 DEF Dosing System Prime Test" using Cat ET to verify that the repair eliminated the problem.
5. Check the Wiring for a Short Circuit A. Disconnect the injector from the harness. B. Connect two 398-4985 Break-out Connectors to the DEF injector harness connector. The connectors must be used to prevent damage to the DEF injector connector. C. Measure the resistance between the following terminals: - The DEF injector positive wire and the DEF injector negative wire at the DEF injector connector. - The DEF injector positive wire and a good ground. -The DEF injector negative wire and a good ground. Note: The resistance between the DEF injector negative wire and a good ground should be greater than 1000 Ohms.	Create a Short	Result: The resistance of the DEF injector wiring harness measured greater than 1000 Ohms. Proceed to Test Step 6. Result: The resistance of the DEF injector wiring harness measured less than 1000 Ohms. There is a short circuit in the wiring harness between the DEF injector connector and the DCU or there is an external short to ground. Repair: Repair or replace the wiring harness. Perform a "Aftertreatment #1 DEF Dosing System Prime Test" using Cat ET to verify that the repair eliminated the problem.
6. Check the Wiring for an Open Circuit A. Disconnect the injector from the harness. B. Disconnect the PETU wiring harness from the DCU. C. Connect two 398-4985 Break-out Connectors to the DEF injector harness connector. The connectors must be used to prevent damage to the DEF injector connector. D. Connect one 398-5062 Break-out Connector to terminal 12 and one 398-5062 Break-out Connector to terminal 32 on the 86-pin DCU connector. The Break-Out Connectors must be used to prevent damage to the DCU connectors. E. Measure the resistance between the following terminals: - Terminal 1 on the DEF injector connector and Terminal 32 on the 86-pin DCU connector. - Terminal 2 on the DEF injector connector and Terminal 12 on the 86-pin DCU connector.	Create an Open	Result: There are more than 10 Ohms of resistance on any one of the DEF injector circuit wires. There is an open in the harness. Repair: Repair or replace the wiring harness. Perform a "Aftertreatment #1 DEF Dosing System Prime Test" using Cat ET to 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).