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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1639 (Theft Deterrent System) >> Diagnostic Information and Procedures >> DTC P1631: PCM Did Not Receive A Valid Password >> Test Description

Test Description

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

2. This DTC may set as a result of other Passlock System problems. Diagnose any BCM DTCs prior to continuing with this diagnostic.

3. A DTC B3031 may set in the body control module (BCM) during the Password Learn Procedure.

Fig 1: DTC P1631
G01577531Courtesy of GENERAL MOTORS CORP.