GM Service Manual Online
For 1990-2009 cars only

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 00: Keyless Entry Antenna 5 Performance - Console Passive Antenna

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Keyless Entry Antenna Signal - LF Door

B3119 00

B3119 00

B3119 00

--

Keyless Entry Antenna Low Reference - LF Door

--

B3119 005

--

--

Keyless Entry Antenna Signal - RF Door

B3120 00

B3120 00

B3120 00

--

Keyless Entry Antenna Low Reference - RF Door

--

B3120 005

--

--

Keyless Entry Antenna Signal - Rear Compartment

B3121 00

B3121 00

B3121 005

--

Keyless Entry Antenna Low Reference - Rear Compartment

--

B3121 00

--

--

Keyless Entry Antenna Signal - Console Passive

B3123 00

B3123 00

B3123 00

--

Keyless Entry Antenna Low Reference - Console Passive

--

B3123 00

--

--

Keyless Entry Antenna Ignition - Console Active

B3122 00

B3122 00

B3122 00

--

Keyless Entry Antenna Data Signal - Console Active

B3122 00

B3122 00

B3122 00

--

Keyless Entry Antenna Clock Signal - Console Active

B3122 00

B3122 00

B3122 00

--

Keyless Entry Antenna Low Reference - Console Active

--

B3122 00

--

--

Circuit/System Description

The console passive antennas is located in the center console and is used to establish low frequency (LF) communications with the keyless entry transmitter. The console antennas 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 (RF) is a valid response, the antenna will determine there is a fob within the vehicle. If no response is received, the antenna determines that no fob is in the vehicle.

Conditions for Running the DTC

A transmitter validation is requested

Conditions for Setting the DTC

An improper current level is seen on the keyless entry antenna - signal (2) 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 console passive antenna.
  2. Place a valid keyless entry transmitter in the pocket located in the center console. This will allow the console active antenna to authenticate the keyless entry transmitter and allow the ignition to be turned on.
  3. Ignition ON, verify a test lamp does not illuminate between the signal circuit terminal A and ground.
  4. If the test lamp illuminates, test the signal circuit for a short to voltage. If the circuit tests normal, replace the RCDLR.
  5. 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.
  6. Attempt to start the vehicle. Verify the DMM captured an AC voltage signal.
  7. 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.
  8. If all circuits test normal, test or replace the console passive antenna.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Ignition Lock Key Transmitter Antenna Replacement - Floor Console
    •  Control Module References for RCDLR replacement, setup, and programming