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 Descriptors

DTC B3123 02: Keyless Entry Antenna 5 Short to Ground
DTC B3123 05: Keyless Entry Antenna 5 High Voltage/Open

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Console --Keyless Entry Passive Antenna Signal | B3123 02 | B3123 05 | B3123 05 | --
Console --Keyless Entry Passive Antenna Low Reference | -- | B3123 05 | -- | --

### Circuit/System Description

The console passive antenna is located in the center console and is used to establish low frequency communications with the keyless entry transmitter. The console antenna is used to determine transmitter placement within the vehicle. When a valid keyless entry transmitter is within the passenger compartment, the console antenna broadcasts a challenge within the passenger compartment to the transmitter. If the response from the transmitter via radio frequency is a valid response, the antenna will determine there is a transmitter within the vehicle. If no response is received, the antenna determines that no transmitter is in the vehicle.

### Conditions for Running the DTC

A transmitter validation is requested

### Conditions for Setting the DTC

#### B3123 02

The keyless entry control module detects a short to ground on the console keyless entry passive antenna circuit.

#### B3123 05

The keyless entry control module detects a short to B+ or an open on the console keyless entry passive antenna circuit.

### Action Taken When the DTC Sets

No action is taken

### Conditions for Clearing the DTC

• | A current DTC will clear when the conditions for setting the DTC are no longer present

• | A history DTC will clear after 50 malfunction free ignition cycles

### Reference Information

#### Schematic Reference

Remote Function Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Keyless Entry System 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 Testing

1. Ignition OFF, disconnect the harness connector at the T10J console passive antenna.
2. Ignition ON, verify a test lamp does not illuminate between the signal circuit terminal A and ground.

⇒ | If the test lamp illuminates, test the signal circuit for a short to voltage. If the circuit tests normal, replace the keyless entry control module.

3. Connect a DMM, set to capture AC voltage using the MIN MAX function, between the signal circuit terminal A and the low reference circuit terminal B.
4. Attempt to start the vehicle. Verify the DMM captured an AC voltage signal.

⇒ | If an AC voltage was not captured, test the signal circuit and the low reference circuit for a short to ground or an open/high resistance. If the circuits test normal, replace the keyless entry control module.

5. If all circuits test normal, test or replace the T10J console passive antenna.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References