Service 4wd message with C0321 code

[waldrop1728]

Looking for some assistance with an '08 Tahoe with the service 4wd message and the C0321 transfer case module lock circuit short to battery code. Any one tackled this before and know how to diagnose? Thanks in advance for any help.

 

[OR VietVet]

DTC-C0321: Motor A or B Circuit Failure Description: DTC-C0321 will be set when the Transfer Case Control Module (TCCM) fi nds a fault in an open lock solenoid, open motor lock control, or an open motor feed. This will cause the 4WD to be disabled and will turn on the “Service 4WD” trouble light. What causes DTC-C0321: 1. The transfer case motor lock feature detects the improper voltage. 2. The Transfer Case Control Module (TCCM) detects no voltage going to the Transfer Case Motor (TCM) lock feature. How to access the diagnostic trouble code (DTC): Once there has been a DTC set, the vehicle will either set a “Service 4WD” light, or the lights on the 4x4 switch will fl ash and/or stay lit. To access the DTCs, you will need to hook up a vehicle diagnostic scanner utilizing the service port under the driver side portion of the dash. When to clear a DTC: The diagnostic trouble code (DTC) should only be erased once the voltage concern has been corrected. How to clear a DTC: 1. The Transfer Case Control Module (TCCM) will clear the DTC once the initial problem has been fi xed. 2. A hard DTC will clear once the vehicle has run through one hundred (100) start cycles and detects no faults. 3. To clear the DTC manually, you will need a vehicle diagnostic scanner (Scan tool). Once the DTC has been erased, go back into the vehicle system and verify that the DTC has been erased and that the system is performing properly


I googled it and found this. Hope it helps. You can just type in "GM code C0321" and then open up all that I saw.

This you tube link may help as well:

 

[Fless]

Could be internal to the encoder motor, or something like this:

 

[waldrop1728]

I replaced the transfer case motor and same error code remains. Anyone have any thoughts as I guess I will look into the TCCM next.

 

[swathdiver]

I replaced the transfer case motor and same error code remains. Anyone have any thoughts as I guess I will look into the TCCM next.View attachment 257528

C0321-01 is for Battery Short - Check voltage wiring and if you have replaced the motor, you have to perform motor learn procedure.

From the Shop Manual:

Circuit/System Testing

The battery positive voltage circuit and the lock solenoid control circuit must be tested for opens, shorts to ground, shorts to voltage, and high resistance. This can also result from a electrically faulted solenoid.

1. With the ignition on check which DTC is set. If DTC C0321 is set with failure type byte 04 then do the following.

¤ The transfer case lock is unable to hold during a hold test and the transfer case actuator will need to be replaced, and the motor learn procedure performed. If this is not the case continue to the next step.

1. Disconnect the transfer case actuator, turn on the ignition and with a DMM check the battery positive voltage circuit for battery voltage at the transfer case actuator.

¤ If battery voltage is not seen then repair the battery positive voltage circuit for an open or high resistance. If the circuit checks out proceed to the next step.

1. Disconnect the transfer case control module connector X2 and check the circuit for an open, high resistance, short to ground, or short to voltage. If condition is found repair the circuit or inline connector 109 as necessary, if the condition is not found refer to component testing.

Component Testing

With the ignition off check the resistance of the lock solenoid with a DMM by probing Pins C and B on the transfer case actuator.

If the resistance reads 16-42 ohms then replace the transfer case control module, program, and complete the motor learn procedure. If the resistance is not in range then replace the transfer case actuator, and complete the motor learn procedure.

 

[waldrop1728]

Replaced the TCCM and retaught the motor and life is good again.....

 

[Fless]

Did you use the Dorman TCCM that doesn't require programming?