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 B1544 01: Mirror Motors Common Circuit Short to Battery

DTC B1544 02: Mirror Motors Common Circuit Short to Ground

DTC B1544 04: Mirror Motors Common Circuit Open

DTC B1600 01: Mirror Motor Vertical Circuit Short to Battery

DTC B1600 02: Mirror Motor Vertical Circuit Short to Ground

DTC B1600 04: Mirror Motor Vertical Circuit Open

DTC B1605 01: Mirror Motor Horizontal Circuit Short to Battery

DTC B1605 02: Mirror Motor Horizontal Circuit Short to Ground

DTC B1605 04: Mirror Motor Horizontal Circuit Open

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Left/Right Mirror Motor Horizontal Control

B1544 04, B1605 02

B1544 04, B1605 04

B1605 01

--

Left/Right Mirror Motor Vertical Control

B1544 04, B1600 02

B1544 04, B1600 04

B1600 01

--

Left/Right Mirror Motor Common Control

B1544 04, B1600 04, B1605 04, B1544 02

B1544 04, B1600 04, B1605 04

B1544 01

--

Circuit/System Description

The Driver Door Module (DDM) or Passenger Door Module (PDM) controls the mirror horizontal and vertical motors through the use of bi-directional motor controls. When the mirror is commanded up and down, voltage or ground is supplied to the mirror vertical motor through the mirror motor up/down control circuit and voltage or ground is supplied through the mirror motor common control circuit.

Horizontal controls operate in the same manner with the mirror motor left/right control circuit supplying voltage or ground and the mirror motor common control circuit suppling voltage or ground to the mirror horizontal motor when the mirror is commanded right and left.

Conditions for Running the DTC

Battery voltage must be between 9-16 volts.

Conditions for Setting the DTC

B1544

An improper voltage level is detected on the mirror motor common control circuit.

B1600

An improper voltage level is detected on the mirror motor vertical control circuit.

B1605

An improper voltage level is detected on the mirror motor horizontal control circuit.

Action Taken When the DTC Sets

Mirror movement is suspended as long as the fault is present.

Conditions for Clearing the DTC

    • A current DTC will clear when the fault is no longer present.
    • A history DTC will clear after 40 fault free ignition cycles.

Reference Information

Schematic Reference

Outside Rearview Mirror Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Outside Mirror 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 Verification

Command the left and right outside mirror to move up, down, left and right using the mirror directional switch. The mirror should move in the commanded direction.

Circuit/System Testing

  1. Ignition OFF, disconnect the X1 harness connector at the appropriate outside rearview mirror.
  2. Connect a test lamp between the control circuit terminal 11 and the control circuit terminal 10.
  3. Ignition ON, command the mirror LEFT and RIGHT with a scan tool. The test lamp should turn ON when commanding the LEFT and RIGHT states.
  4. If the test lamp remains OFF during either of the commands, test for a short to voltage, short to ground or an open/high resistance on either control circuit. If the circuits test normal, replace the appropriate door module.
  5. Connect a test lamp between the control circuit terminal 9 and the control circuit terminal 10.
  6. Ignition ON, command the mirror UP and DOWN with a scan tool. The test lamp should turn ON when commanding the UP and DOWN states.
  7. If the test lamp remains OFF during either of the commands, test for a short to voltage, short to ground or an open/high resistance on either control circuits. If the circuits test normal, replace the door module.
  8. If all circuits test normal, test or replace the outside rearview mirror motor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Outside Rearview Mirror Motor Replacement
    •  Control Module References for DDM or PDM replacement, setup, and programming