C7.1 Engines Caterpillar

Solenoid Valve - Test - Solenoid Valves that Connect to the Dosing Control Unit (DCU)

Usage:

C7.1 881

This procedure covers the following diagnostic codes:

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Table 1
Diagnostic Codes for the Solenoid Valves
J1939 Code	CDL Code	Code Description (code descriptions may vary)	Comments
3361-5	3821-5	Aftertreatment #1 DEF Dosing Unit : Current Below Normal	The ECM detects the following conditions: A low current condition in the output from the DCU to the solenoid in the DEF injector There are no active 168 diagnostic codes. The ECM has been powered for at least 2 seconds. The warning lamp will come on once the diagnostic code has been active for 30 seconds. The diagnostic code will be logged. The engine will be derated while this diagnostic code is active. This diagnostic code detects a fault in the circuit for the DEF injector that is most likely to be an open circuit.
3361-6	3821-6	Aftertreatment #1 DEF Dosing Unit : Current Above Normal	The ECM detects the following conditions: A high current condition in the output from the DCU to the solenoid in the DEF injector. There are no active 168 diagnostic codes. The ECM has been powered for at least 2 seconds. The warning lamp will come on once the diagnostic code has been active for 30 seconds. The diagnostic code will be logged. The engine will be derated while this diagnostic code is active. This diagnostic code detects a fault in the circuit for the DEF injector. This fault is most likely to be caused by a high side short to ground or a low side short to power.
3363-5	3126-5	Aftertreatment #1 DEF Tank Heater : Current Below Normal	The ECM detects the following conditions: A low current condition in the output from the DCU to the solenoid in the coolant diverter valve. There are no active 168 diagnostic codes. The ECM has been powered for at least 2 seconds. The warning lamp will come on once the diagnostic code has been active for 30 seconds. The diagnostic code will be logged. The engine will be derated while this diagnostic code is active. This diagnostic code detects a fault in the circuit for the coolant diverter valve that is most likely to be an open circuit.
3363-6	3126-6	Aftertreatment #1 DEF Tank Heater : Current Above Normal	The ECM detects the following conditions: A high current condition in the output from the DCU to the solenoid in the coolant diverter valve. There are no active 168 diagnostic codes. The ECM has been powered for at least 2 seconds. The warning lamp will come on once the diagnostic code has been active for 30 seconds. The diagnostic code will be logged. The engine will be derated while this diagnostic code is active. This diagnostic code detects a fault in the circuit for the coolant diverter valve. This fault is most likely to be caused by a high side short to ground or a low side short to power.
Follow the troubleshooting procedure to identify the root cause of the fault.

The following background information is related to this procedure:

Coolant Diverter Valve

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Illustration 1	g03795580
Coolant diverter valve

The coolant diverter valve controls the flow of coolant to the heater in the Diesel Exhaust Fluid (DEF) tank. When required, the valve is opened to allow hot coolant to circulate through the DEF tank. This flow allows the coolant to heat the DEF to a useable temperature.

DEF Injector

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Illustration 2	g03795581
DEF injector

The DEF injector controls the flow of DEF into the exhaust stream in the Integrated Clean Emissions Module (IGCEM). The DEF injector is controlled by the Dosing Control Unit (DCU).

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Illustration 3	g03812218
Schematic for the solenoid valves

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Illustration 4	g03812227
Pin locations on the C2 DCU connector for the solenoid valves (8) Coolant diverter valve + (12) DEF injector return (32) DEF injector signal (85) Coolant diverter valve -

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Illustration 5	g03812230
Pin locations on the 12-pin DCU connector for the PETU (1) DEF injector signal (2) DEF injector return

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Table 2
Component	Controller	Electrical Checkout
DEF Injector	Dosing Control Unit (DCU)	DEF Dosing System Verification Test : Initiate the DEF Dosing System Verification test in the electronic service tool to activate the injector circuit.
Coolant Diverter Valve	Dosing Control Unit (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 the ON position. Initiate the DEF Coolant Diverter Valve Solenoid Override in the electronic service tool to activate the coolant diverter valve circuit.

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Table 3
Required Tools
Tool	Part Number	Part Description	Qty
A	372-5260	Test Kit	1

Complete the procedure in the order in which the steps are listed.

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Table 4
Troubleshooting Test Steps	Values	Results
1. Inspect Electrical Connectors and Wiring A. Thoroughly inspect the 12-pin connector for the PETU and the C2 DCU connector. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details. B. Thoroughly inspect the connector for the suspect solenoid valve. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details. C. Perform a 45 N (10 lb) pull test on each of the wires in the 12-pin connector for the PETU, the C2 DCU connector, and the solenoid connectors that are associated with the active diagnostic code. D. Check the harness for corrosion, abrasion, and pinch points from the solenoids to the ECM.	Loose connection or damaged wire	Result: There is a fault in a connector or the wiring. Repair: Repair any faulty connectors or replace the wiring harness. Ensure that all the seals are properly in place and ensure that the connectors are correctly coupled. Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault. Result: All connectors, pins, and sockets are correctly coupled and/or inserted. The harness is free of corrosion, abrasion, and pinch points. Proceed to Test Step 2.
2. Check for Active Diagnostic Codes A. Turn the keyswitch to the OFF position. B. Connect the electronic service tool to the diagnostic connector. C. Turn the keyswitch to the ON position. Wait at least 20 seconds for activation of the diagnostic codes. D. Verify if any of the diagnostic codes that are listed in Table 1 are active. E. Turn the keyswitch to the OFF position.	Diagnostic codes	Result: A 3363-5 or 3126-5 diagnostic code is active. Proceed to Test Step 3. Result: A 3363-6 or 3126-6 diagnostic code is active. Proceed to Test Step 4. Result: A 3361-5, 3821-5 , 3361-6 or 3821-6 diagnostic code is active. Proceed to Test Step 5.
3. 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 applicable harness. C. Connect a jumper wire between the terminals of the harness connector for the suspect coil. The coil is replaced with a short circuit. D. Perform the appropriate electrical checkout. Refer to Table 2.	Wiring	Result : A -5 code became active during the electrical checkout. There is an open circuit in the wiring between the coil and the applicable ECM connector. Repair : Repair the connectors and/or the wiring. 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, the code to reset, and the DCU to reset. Verify that the original fault is resolved. If the fault is still present, contact the Dealer Solutions Network (DSN). Result : A -6 code is activated during the electrical checkout. The DCU detected the jumper wire. There is a fault in the solenoid. Repair : Replace the solenoid. Perform the electrical checkout again to verify that the fault is resolved.
4. Check the Wiring for a Short Circuit A. Disconnect the solenoid from the applicable harness. B. Perform the appropriate electrical checkout. Refer to Table 2.	Wiring	Result : A -6 code became active during the electrical checkout. The DCU did not detect the open circuit. There is a short circuit in the wiring between the coil and the applicable ECM connector. Repair : Repair the connectors and/or the wiring. 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, the code to reset, and the DCU to reset. Perform the electrical checkout again to verify that the fault is resolved. If the fault is still present, contact the Dealer Solutions Network (DSN). Result : A -5 code is activated during the electrical checkout. The applicable ECM detected the open circuit. There is a fault in the solenoid. Repair : Replace the solenoid. 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, the code to reset, and the DCU to reset. Perform the electrical checkout again to verify that the fault is resolved.
5. Measure the Resistance of the Injector A. Turn the keyswitch to the OFF position. 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 from Tooling (A) 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.	10 to 20 Ohms	Result : The resistance of the injector measured between 10 Ω and 20 Ω. Proceed to Test Step 6. Result : The resistance of the injector did not measure between 10 Ω and 20 Ω. A failed DEF injector has been detected. Repair : Replace the injector. Refer to the Disassembly and Assembly manual for the correct procedure. Use the electronic service tool to perform a DEF Dosing System Verification test. This test will verify that the fault is resolved.
6. Check for a Short Circuit in the Wiring Harness A. Disconnect the injector from the harness. B. Connect two 398-4985 Break-out Connectors from Tooling (A) 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 DEF injector positive wire and the DEF injector negative wire at the DEF injector harness connector. D. Measure the resistance between the DEF injector positive wire and a good ground. E. Measure the resistance between the DEF injector negative wire and a good ground. The resistance should be greater than 1kΩ.	Greater than 1k Ohms	Result : The resistance of the DEF injector wiring harness measured greater than 1k Ω. Proceed to Test Step 7. Result : The resistance of the DEF injector wiring harness measured less than 1k Ω. 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. Use the electronic service tool to perform a DEF Dosing System Verification test. This test will verify that the fault is resolved.
7. Check for an Open Circuit in the Wiring Harness A. Disconnect the injector from the harness. B. Disconnect the PETU wiring harness from the DCU. C. Connect two 398-4985 Break-out Connectors from Tooling (A) to the DEF injector harness connector. The connectors must be used to prevent damage to the DEF injector connector. D. Connect one 398-5063 Break-out Connector from Tooling (A) to terminal 12. Connect one 398-5063 Break-out Connector from Tooling (A) 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 terminal 1 on the DEF injector connector and terminal 32 on the 86-pin DCU connector. F. Measure the resistance between terminal 2 on the DEF injector connector and terminal 12 on the 86-pin DCU connector.	Less than 10 Ohms	Result: There is more than 10 Ω of resistance on any one of the DEF injector circuit wires. There is an open in the harness. Repair : Repair the wiring or replace the harness. Use the electronic service tool to perform a DEF Dosing System Verification test. This test will verify that the fault is resolved. Result: There is less than 10 Ω of resistance on any one of the DEF injector circuit wires. The harness is OK. Contact the Dealer Solutions Network (DSN).