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 B3122 02: Keyless Entry Antenna 4 Short to Ground
DTC B3122 05: Keyless Entry Antenna 4 High Voltage/Open

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Console --Keyless Entry Active Antenna Signal | B3122 02 | B3122 05 | B3122 05 | --
Console --Keyless Entry Active Antenna Low Reference | -- | B3122 05 | -- | --

### Circuit/System Description

The console active antenna is located in the center console and is used to establish low frequency communications with the keyless entry transmitter The keyless entry console active antenna is only used when the console passive antenna was unable to locate a transmitter within the interior of the vehicle. This may be due to a keyless entry transmitter battery being low or radio/low frequency interference.

When a valid transmitter is placed into the pocket located in the center console, and either the brake pedal is depressed or the ignition switch is pressed, the console active antenna broadcasts a challenge to the transmitter. This causes a low frequency coupling to occur between the transmitter and the console active antenna. If the response from the transmitter is a valid response, and all of the security requirements are met, the vehicle's engine will start, or be allowed to go into accessory mode.

### Conditions for Running the DTC

The console active antenna is activated

### Conditions for Setting the DTC

#### B3122 02

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

#### B3122 05

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

### Action Taken When the DTC Sets

The vehicle will not start or go into accessory mode.

### 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 T10A console active antenna.
2. Ignition OFF, test for less than 20 Ω between the low reference circuit terminal 5 and ground.

⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the keyless entry control module.

3. Ignition ON, test for B+ between the B+ voltage circuit terminal 2 and ground while commanding the scan tool Active Antenna output control ON.

⇒ | If not the specified value, test the B+ voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the keyless entry control module.

4. Ignition OFF, disconnect the X2 harness connector at the keyless entry control module.
5. Ignition ON, verify a test lamp does not illuminate between the signal circuits listed below and ground:

• | Terminal B

• | Terminal C

⇒ | If the test lamp illuminates, test the signal circuit for a short to voltage.

6. Ignition OFF, test for infinite resistance between the signal circuits listed below and ground:

• | Terminal B

• | Terminal C

⇒ | If less than the specified value, test the signal circuit for a short to ground.

7. Test for less than 2 Ω between the signal circuits listed below:

• | Terminal B at the keyless entry control module and terminal 3 at the console active antenna

• | Terminal C at the keyless entry control module and terminal 4 at the console active antenna

⇒ | If greater than the specified range, test the signal circuit for an open/high resistance.

8. If all circuits test normal, test or replace the T10A console active antenna.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References