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 B1265 02: Switched 14 Volt Performance Short to Ground

Circuit/System Description

When the navigation radio is on, a discrete 12-volt signal is supplied on the Entertainment Remote Enable Signal circuit to the Display Module, Display Actuator, Antenna module, and Amplifier (UQA). This signal is used to control the power state of the modules.

Conditions for Running the DTC

The following are conditions that must be present in order for the navigation radio to enable diagnostics:

    • The ignition must be in the RUN or ACC position.
    • The system voltage is at least 9.5 volts and no more than 15.5 volts.

Conditions for Setting the DTC

    • The navigation radio detects a short to ground on the Entertainment Remote Enable Signal circuit.
    • All the above conditions are present for greater than 250 mS.

Action Taken When the DTC Sets

The Display Module, Display Module Actuator, Antenna module, and Audio Amplifier (UQA) may become inoperative.

Conditions for Clearing the DTC

    • The condition for setting the DTC no longer exists.
    • A history DTC clears after 50 malfunction-free ignition cycles.

Diagnostic Aids

    • This DTC may be stored as a history DTC without affecting the operation of the navigation radio.
    • If stored only as a history DTC and not retrieved as a current DTC, do not replace the navigation radio.

Reference Information

Schematic Reference

Radio/Navigation System Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Navigation 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

Note: The ignition circuit controls multiple modules/components. Each of the modules will need to be disconnected if the ignition circuit test fails for a short to voltage or short to ground. Disconnect one module/component at a time while testing the ignition circuit for a short to voltage or short to ground. If the fault is no longer present when disconnecting a module/component replace that module/component. If the fault is still present with all the module/component disconnected repair the circuit.

  1. Ignition OFF, disconnect one of the connectors listed below at an inoperative module/component:
  2. • Antenna Module
    • Radio/HVAC Display X1
    • Radio/HVAC Display X2
    • Audio Amplifier X3 (UQA only)
  3. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal listed below and ground.
  4. • Antenna Module -- terminal 1
    • Radio/HVAC Display X1 -- terminal 4
    • Radio/HVAC Display X2 -- terminal 3
    • Audio Amplifier (UQA only) -- terminal 8
    If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal replace the Radio.
  5. If all circuits test normal, replace the module/component that was disconnected in step 1.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

    •  Control Module References for radio and amplifier replacement, programming, and Setup
    •  Radio Antenna Module Replacement for radio antenna module replacement
    •  Radio, Video, Audio Disc Player, and Navigation Information Display Replacement for navigation display replacement