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 Descriptor

DTC B3103 : Keyless Entry Data Link Circuit High

Diagnostic Fault Information

Circuit

Short to Ground

Short to Voltage

Parity

Signal Performance

Keyless Entry Data Link Circuit

B3102

B3101, B3103

B3106

B3101

Circuit/System Description

The remote control door lock receiver (RCDLR) communicates with the body control module (BCM) through the keyless entry serial data circuit. When any button on the keyless entry transmitter is pressed, the transmitter sends a signal to the RCDLR. The RCDLR sends a lock, unlock, or panic alarm request to the BCM, depending on which button is pressed on the transmitter. The BCM receives the message and performs the appropriate function. The BCM also uses the keyless entry serial data circuit in order to communicate with the RCDLR when programming transmitters.

Conditions for Running the DTC

    • The system voltage is at least 9 volts and no more than 16 volts.
    • The BCM must be receiving a message from the RCDLR while in the program mode.

Conditions for Setting the DTC

The BCM detects a short to voltage in the keyless entry serial data circuit.

Action Taken When the DTC Sets

The keyless entry system will not operate.

Conditions for Clearing the DTC

    • A current DTC will clear when the fault is no longer present and the ignition switch is cycled.
    • The history DTC will clear after 100 consecutive ignition cycles without a fault present.
    • A scan tool may be used to clear history and current DTCs.

Reference Information

Schematic Reference

Remote Function Schematics

Connector End View Reference

Remote Function Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Scan Tool Data List

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the RCDLR.
  2. Ignition ON, verify that a test lamp does not illuminate between the keyless entry serial data circuit and ground.
  3. If the test lamp does illuminate, test the keyless entry serial data circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  4. If all circuits test normal, test or replace the RCDLR.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for BCM or RCDLR replacement, setup, and programming