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 B3031: Security System Controller In Learn Mode

### Circuit/System Description

When a body control module (BCM) is replaced, it must be programmed to accept the analog voltage signal code of the existing Passlock™ sensor. When the BCM is replaced, the service replacement BCM is programmed to accept the first Passlock™ code it detects. If the BCM is unable to detect a valid Passlock™ code, the BCM will never end the programming sequence and DTC B3031 will continue to be set as current.

In this mode, the BCM will learn the current Passlock™ sensor code value.

### Conditions for Setting the DTC

• | A new BCM has been installed and the ignition is turned to the ON position but not rotated to the CRANK position. Once the ignition switch has been rotated to the CRANK position, the BCM will learn the Passlock™ code. The theft relearn procedure will need to be run in order to make the engine control module (ECM) receive the correct fuel enable password.

• | The BCM is in the learn mode but does not see a valid Passlock™ sensor code because of a sensor or a wiring problem.

### Action Taken When the DTC Sets

• | The BCM stores DTC B3031 in the BCM memory as a current DTC.

• | 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 current DTC B3031 changes to history when the BCM detects a valid Passlock™ sensor code.

• | A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.

### Diagnostic Aids

• | If there is an open or short in any of the Passlock™ sensor circuits, the BCM will be unable to read a valid code from the Passlock™ sensor when the program mode is active.

• | Always diagnose all other Passlock™ DTCs first before diagnosing this DTC. These DTCs will affect the BCM ability to properly read a Passlock™ code.

• | If DTC B3031 is set in the BCM as a history DTC, clear the DTC and recheck the system. A history DTC B3031 indicates that the BCM has successfully completed the programming mode.

### 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

1. Install the scan tool. Attempt to CRANK but do not start the vehicle and release the ignition switch to ON. Verify DTC B3031 is set as current.

⇒ | If DTC B3031 is set as current, along with DTC B2957 or B2958, proceed to diagnose DTC B2957 or DTC B2958 .

2. Perform the Programming Theft Deterrent System Components procedure.
3. After programming check for DTC B3031. If DTC B3031 resets as current, replace the BCM. Refer to BCM replacement in Repair Instructions.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for BCM replacement, setup, and programming