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.

Circuit/System Description

The garage door opener (GDO) is a transmitter operating between 288 and 399 MHz. The GDO has three buttons that may be programmed for individual transmitter/receiver combinations to control up to three GDOs, security gates, lighting systems, etc. Each button represents a unique transmitter code section, which operates independently of the other buttons, and may be considered a separate transmitter.

Reference Information

Schematic Reference

Remote Function Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Garage Door Opener 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

Special Tools

J 41540 Universal Home Remote Tester

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the GDO.
  2. Ignition OFF, test for less than 5 ohms of resistance between the ground circuit terminal 3 and ground.
  3. If greater than the specified value, test the ground circuit for an open/high resistance.
  4. Ignition ON, verify a test lamp illuminates between the B+ circuit terminal 1 and ground.
  5. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

    Important: This step will clear any learned transmitters from the GDO. This will require reprogramming by the customer to reestablish GDO functionality.

  6. Ignition ON, hold the two outer buttons on the GDO for 30 seconds. After 20 seconds, the LEDs will flash indicating that all learned transmitter values have been cleared. After an additional 10 seconds, the LEDs will flash again indicating it has entered the diagnostic mode. Place the J 41540 adjacent to the GDO and press each button of the GDO one at a time. The tester should indicate when each button is pressed.
  7. If the tester indicates that one or more of the buttons does not respond, replace the GDO.
  8. Instruct the customer to program the GDO. Refer to the vehicle owners manual. A possible rolling code or incompatibility with the GDO receiver will prevent programming. Refer to www.learcar2u.com or 1-866-572-2728.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for GDO replacement, setup, and programming