For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### DTC Descriptor

DTC P1630: Theft Deterrent Learn Mode Active

### Circuit/System Description

The Theft Deterrent System is incorporated within the body control module (BCM). If the BCM has been replaced, the password must be relearned. If the engine control module (ECM) is replaced, the replacement ECM should learn the password within a few seconds after the ignition is turned ON. This is an information code indicating that the ECM is ready to learn the theft deterrent password.

### Conditions for Running the DTC

• | The Theft Deterrent System has allowed fuel delivery.

• | The ECM is in the theft deterrent password learn mode.

### Conditions for Setting the DTC

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

### Action Taken When the DTC Sets

• | The ECM will not illuminate the malfunction indicator lamp (MIL).

• | The ECM will store conditions which were present when the DTC set as Failure Records data only. This information will not be stored as Freeze Frame data.

### Conditions for Clearing the DTC

• | A History DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.

• | The DTC can be cleared by using a scan tool.

### Diagnostic Aids

A new replacement ECM will be in a functional state to learn the password from the BCM. If the BCM is replaced, the ECM 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 ECM battery or ignition voltage will not affect the programmed password information.

### Reference Information

#### Schematic Reference

Immobilizer Schematics

#### Connector End View Reference

Master Electrical Component List

#### Description and Operation

Immobilizer Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

• | Scan Tool Data List

• | Scan Tool Data Definitions

### Circuit/System Testing

Complete the password learn procedure. Refer to Programming Theft Deterrent System Components .

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for BCM replacement, setup, and programming