GM Vehicle Anti-Theft System Password Relearn

GM Vehicle Anti-Theft System Password Relearn

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When your GM vehicles replace Passlock (TM) sensor,body control (BCM) or powertrain control module (PCM) or vehicle control module(VCM),you must perform a theft system password learn.And for more immobilizer article,please check here:Auto Key Program

The above modules, with the exception of the Passlock (TM) Sensor, must also be programmed with each module’s own vehicle configuration. See the individual module service manual section.

Password Learn Procedure For Anti-Theft System (4.3L, 5.0L, 5.7L & 7.4L)

1.Password learn procedure must be performed if Vehicle Control Module (VCM), passlock module or passlock sensor is replaced. A password is communicated between VCM and passlock module to provide engine operation.

If VCM is replaced, the VCM must learn the password from the passlock module.

NOTE: Ensure battery is fully charged before proceeding. Performing this procedure will cause a Diagnostic Trouble Code (DTC) P1630 to be set in the VCM. It will be necessary to use the SPS Device to check for DTC P1630 when performing this procedure. Ensure steps are followed in correct order or procedure may need to be repeated.

2.Attempt to start engine. Engine will start and then stall. After engine stalls, leave ignition on for 10 minutes. After engine stalls, the SECURITY indicator light will come on for 10 minutes and then go off. The SECURITY indicator light is located on upper right corner of instrument panel, just above battery charge indicator.

3.After SECURITY indicator light goes off, turn ignition off for 30 seconds. Attempt to start engine and then leave ignition on. After engine has stalled, leave ignition on for 10 minutes. SECURITY indicator light will come on for 10 minutes and then go off. After SECURITY indicator light goes off, turn ignition off for 30 seconds.

4.Attempt to start engine and then leave ignition on. After engine has stalled, leave ignition on for 10 minutes. SECURITY indicator light will come on for 10 minutes and then go off or until DTC 1630 is set in VCM.

NOTE: DTC 1630 will be set in VCM as result of this procedure. DTC P1630 may be cleared from VCM by turning ignition off for 30 seconds and then turning ignition on again.

5.Turn ignition off for 30 seconds. Turn ignition on and wait 30 seconds. Attempt to start engine. If engine starts, password learn procedure is complete. Ensure DTC 1630 is cleared from VCM by turning ignition off for 30 seconds and then turning ignition on again. If DTC 1630 is not cleared from VCM, perform test procedures for DTC 1630 and repair as necessary.

6.If engine does not start, ensure procedure was properly followed. If procedure was properly followed, check for any DTCs. If any DTCs exist, perform test procedures for specified DTC and repair as necessary.

Password Learn Procedure For Anti-Theft System (6.5L Diesel)

1.Password learn procedure must be performed if Powertrain Control Module (PCM), passlock module or passlock sensor is replaced. A password is communicated between PCM and passlock module to provide engine operation.

If PCM is replaced, the PCM must learn the password from the passlock module.

NOTE: Ensure battery is fully charged before proceeding. Performing this procedure will cause a Diagnostic Trouble Code (DTC) P1630 to be set in the PCM. It will be necessary to use the SPS Device to check for DTC P1630 when performing this procedure. Ensure steps are followed in correct order or procedure may need to be repeated.

2.Attempt to start engine. Engine will start and then stall. After engine stalls, leave ignition on for 10 minutes. After engine stalls, the SECURITY indicator light will come on for 10 minutes and then go off.

The SECURITY indicator light is located on upper right corner of instrument panel, just above battery charge indicator.

3.After SECURITY indicator light goes off, turn ignition off for 30 seconds. Attempt to start engine and then leave ignition on. After engine has stalled, leave ignition on for 10 minutes. SECURITY indicator light will come on for 10 minutes and then go off. After SECURITY indicator light goes off, turn ignition off for 30 seconds.

4.Attempt to start engine and then leave ignition on. After engine has stalled, leave ignition on for 10 minutes. SECURITY indicator light will come on for 10 minutes and then go off or until DTC 1630 is set in PCM.

NOTE: DTC 1630 will be set in PCM as result of this procedure. DTC P1630 may be cleared from PCM by turning ignition off for 30 seconds and then turning ignition on again.

5.Turn ignition off for 30 seconds. Turn ignition on and wait 30 seconds. Attempt to start engine. If engine starts, password learn procedure is complete. Ensure DTC 1630 is cleared from PCM by turning ignition off for 30 seconds and then turning ignition on again. If DTC 1630 is not cleared from PCM, perform test procedures for DTC 1630 and repair as necessary.

6.If engine does not start, ensure procedure was properly followed. If procedure was properly followed, check for any DTCs. If any DTCs exist, perform test procedures for specified DTC and repair as necessary.

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