HiCustomer Thank you for asking your question on Just Answer. The other Experts and I are working on your answer. By the way, it would help us to know:-What year is your Chevy?-What model is your Chevy?-How many miles are on your Chevy?-What type of engine is in your Chevy?-What have you already tried?Thank you again for trusting us with your problem. Please reply as soon as possible so that we can finish answering your question. Did you scan the vehicles computer system to see what failure code was set ?
If so,what was the code or codes?
Try this first.Maybe your lock cylinder was faulty.
Important: If a new vehicle control module (VCM) is being installed for the first the manufacturing enable bit will be set and the auto learn procedure may not be necessary.
The following procedure allows for anyone to reprogram the passlockTM module learned data code with any tools, other than the scan tool, when any of the following parts are replaced:
The passlockTM module will set the DTC B3031 module in the learn mode when entering the reprogramming procedure.
Important: Erase the passlockTM related diagnostic trouble codes (DTCs) that are stored in the VCM. If there are any powertrain related DTCs, record these DTCs and refer to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls - 4.3L
The following is the Auto Learn Procedure:
How did this problem start out.Did you have a no start vehicle & if so,was the security light on or flashing?Was there an original failure code?