Test Description

The numbers below refer to the step numbers on the diagnostic table. See Fig 1 and Fig 2 .

1. 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.
2. 5
   
   Tests for an open in the Passlock™ sensor signal circuit, which may not set a DTC (B2958) under certain conditions.
3. 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.
4. 7
   
   The presence of DTC P0601, P0602 or P0604 indicates an internal fault in the PCM.
5. 8
   
   The presence of DTC B1000 indicates an internal module fault.
6. 9
   
   The Presence of DTC P0562, P0563 or P0621 indicates a low or high voltage condition.
Fig 1: Diagnostic System Check - Theft Deterrent Diagnostic Table (Steps 1-6)
Courtesy of GENERAL MOTORS CORP.

Fig 2: Diagnostic System Check - Theft Deterrent Diagnostic Table (Steps 7-9)

Courtesy of GENERAL MOTORS CORP.