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 B3055 00: No Transponder Modulation or No Transponder

### Circuit/System Description

When an ignition key is inserted into the ignition lock cylinder and the ignition is switched ON, the transponder embedded in the key is energized by the exciter coils surrounding the ignition lock cylinder. The transponder transmits a signal to the body control module (BCM). The BCM then compares this value to a value stored in memory. If the value is correct, the BCM will send the prerelease password via the serial data circuit to the engine control module (ECM). If the learned key code does not match or a transponder value is not received, the BCM will send the start disable password to the ECM.

### Conditions for Running the DTC

Ignition is in the Accessory or Run position.

### Conditions for Setting the DTC

The BCM is unable to measure the ignition key transponder value.

### Action Taken When the DTC Sets

• | Vehicle starting will be disabled.

• | The security indicator in the instrument cluster will be illuminated. A service message will be displayed in the driver information center.

### Conditions for Clearing the DTC

• | A current DTC will be cleared when the BCM detects a valid transponder value from the ignition key.

• | A history DTC will be cleared after 100 malfunction-free ignition cycles or when a scan tool is used to clear DTCs.

### Reference Information

#### Schematic Reference

Immobilizer Schematics

#### Connector End View Reference

Component Connector End Views

#### 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

Control Module References for scan tool information

### Circuit/System Verification

1. Inspect all available vehicle keys that they are correct vehicle keys.

⇒ | If not a correct vehicle key, replace the key.

2. While viewing the scan tool BCM Transponder Key Communication, turn ON the ignition with each of the available vehicle keys. The parameter should read ID Received with all available keys.

⇒ | If only one key results in the parameter reading Inactive, replace the appropriate key.

⇒ | If all available keys result in the parameter reading Inactive, test the control circuit terminal 26 (X1) and 27 (X2) at the BCM for a short to voltage or an open/high resistance. If the circuit tests normal replace the K84 Remote Function Receiver Module and verify the parameter should read ID Received with all available key. If the parameter reading is Inactive replace the K9 Body Control Module (BCM)

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Replacing Keys

• | Control Module References for BCM and remote function receiver module replacement, setup, and programming.