Test Description

WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, and 2003 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers on the diagnostic table.

2. Lack of communication may be due to a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.

5. Tests for an open in the passlock sensor signal circuit which may not set a DTC B2958 under certain conditions.

6. The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed.

7. The presence of DTC P0601, P0602, P0604, or P0606 indicates an internal fault in the PCM.

8. The presence of DTC B1000 indicates an internal module fault.

9. The presence of DTC P1637, P1638, P0562 or P0563 indicates a low or high voltage condition.

Fig 1: Theft Deterrent - Diagnostic Chart (Steps 1 - 2)

Courtesy of GENERAL MOTORS CORP.

Fig 2: Theft Deterrent - Diagnostic Chart (Steps 3 - 9)

Courtesy of GENERAL MOTORS CORP.