B3122

DTC B3122

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.



DTC Descriptor
DTC B3122
- Keyless Entry Antenna 4 Performance




Diagnostic Fault Information






Circuit/System Description

The back up keyless entry antenna is located in the glove compartment area and is used as a short range low frequency (LF) transmitter. When a valid key fob is within the passenger compartment and the brake pedal is depressed and the ignition button is pressed the keyless entry antenna transmitter broadcasts a challenge within the passenger compartment to the key fob. If the response from the key fob via radio frequency (RF) is a valid response and all the security requirement are met the vehicles engine will start or be able to go into accessory mode.


Conditions for Running the DTC

A transmitter validation is requested.


Conditions for Setting the DTC

An improper voltage level is seen on the keyless entry antenna - back up signal circuit.


Action Taken When the DTC Sets

The back up keyless entry antenna is ignored.


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 (Remote Function Schematics)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Keyless Entry System Description and Operation (Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for Scan Tool Information


Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the back up keyless entry 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 RCDLR.

3. Ignition OFF, install a DMM between the signal circuit terminal A and the low reference circuit terminal B. Set the DMM to capture AC voltage using the MIN MAX function.
4. Ignition ON, 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 RCDLR.

5. If all circuits test normal, test or replace the back up keyless entry antenna.



Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Ignition Lock Key Transmitter Antenna Replacement - Instrument Panel (Ignition Lock Key Transmitter Antenna Replacement - Instrument Panel)
* Control Module References (Programming and Relearning) for RCDLR replacement, setup, and programming