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DTC B154A or B154B

DTC B154A or B154B

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 B154A 39

Driver Mirror Internal Malfunction

DTC B154B 39

Passenger Mirror Internal Malfunction

Circuit/System Description

The outside rearview mirror switch is a multiplex switch which signals the left mirror control module which outside rearview mirror to move (driver or passenger) and which direction to move it. The left mirror control module and the passenger window switch are on a serial data circuit with the memory seat module as the master. The mirror select and directional control switches are inputs to the left mirror control module. When the memory seat module receives the switch inputs from the left mirror control module, mirror output commands are sent to the appropriate switch through the serial data circuit. The left mirror control module and passenger window switch control the left and right outside rear view mirrors through bi-directional motor control circuits. The motor control circuits are floating while in an inactive state and the switches will apply power and ground to the control circuits as necessary to move the mirror in the commanded direction.

Mirror position is determined by both horizontal and vertical position sensors in each of the power mirrors. The left mirror control module and passenger window switch supply a 5 V reference, low reference, and horizontal and vertical position signal circuits to these sensors. The signal circuits are referenced from 5 V by the switches and the signal circuit voltage levels represent the mirror positions. The mirror positions are sent to the memory seat module through the serial data circuit where they are stored for memory mirror operation. When the memory seat module receives a memory recall command, the memory seat module will send the go to position commands to the left mirror control module and passenger window switch. The switches will then drive the appropriate mirror motors to the commanded position sensor settings.

Conditions for Running the DTC

Battery voltage must be between 9-16 V.

Conditions for Setting the DTC

B154A 39

The left mirror control module has determined that a hardware or software error has occurred.

B154B 39

The passenger window switch has determined that a hardware or software error has occurred.

Action Taken When the DTC Sets

Power mirror functions are 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 (without AAB) Outside Mirror Description and Operation (With AAB)

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

If the DTC is set, replace the appropriate K96L left mirror control module or the S79P passenger window switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for left mirror control module or passenger window switch replacement, setup, and programming