For 1990-2009 cars

Refer to Engine Controls Schematic Engine Controls Schematics .

### Circuit Description

The theft deterrent system is incorporated within the body control module (BCM). If the BCM has been replaced, the password must be relearned using approved Techline diagnostic equipment. If the powertrain control module (PCM) is replaced, the replacement PCM should learn the password within a few seconds after the ignition is turned ON. DTC P1630 is an information code indicating that the PCM is ready to learn the theft deterrent password. The engine will start and continue to run with DTC P1630 set. Refer to Vehicle Theft Deterrent (VTD) Description in Theft Deterrent.

### Conditions for Running the DTC

• | The theft deterrent system has allowed fuel delivery.

• | The PCM is in the theft deterrent Password Learn mode.

### Conditions for Setting the DTC

The PCM remains in theft deterrent password learn mode for more than 2 seconds.

### Action Taken When the DTC Sets

The PCM stores conditions which were present when the DTC set as Failure Records only. This information will not be stored as Freeze Frame Records.

### Conditions for Clearing the MIL/DTC

• | The DTC becomes history when the conditions for setting the DTC are no longer present.

• | The history DTC clears after 40 malfunction free warm-up cycles.

• | The PCM receives a clear code command from the scan tool.

### Diagnostic Aids

A new replacement PCM will be in a functional state to learn the password from the BCM. If the BCM is replaced, the PCM must be placed in Password Learning mode to relearn a new password. Once learned, the password becomes permanent information that remains with the vehicle. The loss of PCM battery or ignition voltage will not affect the programmed password information.

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Powertrain On Board Diagnostic (OBD) System Check? | -- | Go to Diagnostic System Check - Theft Deterrent in Theft Deterrent | Go to Powertrain On Board Diagnostic (OBD) System Check