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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1852 (Immobilizer System) >> Diagnostic Information and Procedures >> DTC P1631 >> Test Description

Test Description

WARNING: This page is about a different car, the 2007 Saturn Vue. 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.

  1. 2:  This DTC may set as a result of other Passlock™ System problems. Diagnose any BCM DTCs prior to continuing with this diagnostic.
  2. 3:  A DTC B3031 may set in the BCM during the Password Learn Procedure.
DTC P1631

Step Action Yes No
Schematic Reference: Data Communication Schematics
1 Did you perform the Diagnostic System Check - Vehicle? Go to Step 2  Go to Diagnostic System Check - Vehicle
2 
IMPORTANT: You must diagnose the Bxxxx codes prior to diagnosing any Pxxxx code.
  1. Install a scan tool.
  2. Momentarily rotate the ignition switch to CRANK. Do not start the vehicle.
  3. Release the ignition switch to ON.
  4. Select the powertrain control module display DTCs function on the scan tool.
Does the scan tool display DTC P1631 as a current DTC?		 Go to Step 3  Go to Testing for Intermittent Conditions and Poor Connections
3  Perform the Passlock™ Programming procedure. Refer to Programming Immobilizer System Components .
Did the powertrain control module (PCM) successfully learn the password?		 Go to Step 4  Go to Diagnostic System Check - Vehicle
4
IMPORTANT: Before clearing DTCs, monitor all DTC status parameters and note any additional DTCs.
  1. Clear the PCM DTCs.
  2. Turn OFF the ignition for 30 seconds.
  3. Attempt to start the engine.
Does the engine start and operate normally?		 System OK Go to Step 2 
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