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Pete, Auto Service Technician
Category: Chevy
Satisfied Customers: 28308
Experience:  14 years GM dealer Technician.
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2005 Chevy Silverado 1500: Control Module..service 4x4 drive error

Resolved Question:

I have a 2005 Chevy Silverado 1500 Z21, I have replaced the TCCM (Transfer Case Control Module). The TCCM was programmed by the dealer. I am still recieving a service 4x4 drive error on my lcd panel, but now the TCCM can comunicate with the scan tool. When I start the car the switch box illuminates (Auto,2wd...ect). When I hit a button before or after the 4x4 service message nothing happens. I got the switch box tested and everything is in working order. Before I got the new TCCM I was able to switch to 4x4 intermediately. The technician said that the Transfer Case Encoder Motor had to be replaced. Since I was able to shift into 4wd before the replacement of the TCCM do I really need the whole assembly? Do I need to replace the Transfer Case Encoder Motor or can I just replace the Transfer Case Encoder Motor Sensor and gasket?
Submitted: 5 years ago.
Category: Chevy
Expert:  Pete replied 5 years ago.
Hello,I will be glad to try and assist you with this,Welcome to Just Answer.


I just need a little more info to assist better.

Have the fault codes been rechecked since the TCCM was replaced and if so do you know the fault code number that is set?

Were you not able to communicate with the old TCCM?

Let me know so we can continue,Thanks Pete!
Customer: replied 5 years ago.
The code that the technicain pulled off the scan tool was C0327 Encoder Circuit Malfunction. Yes, the tech was not able to communicate with the TCCM until it was replaced. The rpo for the transfercase is np8. This code was checked then cleared and rechecked again, it kept comming up.
Expert:  Pete replied 5 years ago.

The code you have set does correspond with the sensor in the encoder motor on the transfer case failing which will cause this issue you have here on this vehicle.The only thing that would make me think it needs the entire encoder motor is the case that the old TCCM could not be communicated with because in some cases the encoder motor can short internally and this short can feed back to the TCCM and short out the TCCM to where it cannot be communicated with.This may be the case here and maybe why he/she wants to replace the entire motor.

This code can also indicate the encoder motor is at fault needing replaced,in most cases when it is just the sensor the TCCM can be communicated with.The sensor is the cheaper repair here but its hard to say for sure from here if it will correct this issue or if you need the entire encoder motor.

I would ask the mechanic what kind of guarantee he/she will give that this will correct the issue and if it doesn't if they will cover the costs of the next repair.

Let me know if you need anything else,click accept if you feel satisfied with your answer as this is how I get credited for my time,Thanks Pete!
Pete and 5 other Chevy Specialists are ready to help you
Customer: replied 5 years ago.
Do you know the part number of the Encoder motor?
Expert:  Pete replied 5 years ago.
The number I come up with for this (this should be double checked by a dealers parts department) is 88984528.You can also get one of these from a local parts store for a cheaper cost.I don't know the after market part numbers as these vary depending on manufacturer.

Let me know if you need anything else,click accept if you feel satisfied with your answer as this is how I get credited for my time,Thanks Pete!