B1721

DTC B1721

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

DTC Descriptor
DTC B1721
- Mirror Left and Right Control Switch Circuit

Diagnostic Fault Information





Circuit/System Description

The driver door module (DDM) supplies battery positive voltage to the power mirror switch. When the mirror direction switch is placed in the up or down position, the appropriate signal circuit is switched to battery voltage. The driver door module senses the voltage change and activates the selected outside rearview mirror in the appropriate direction.

Conditions for Running the DTC

Battery voltage must be between 9-16 volts.

Conditions for Setting the DTC

The DDM senses an active state on both the mirror switch left and right signal circuits greater than 3 seconds.

Action Taken When the DTC Sets

The DDM ignores the continuous inputs from the switch. The DDM will respond to all other valid switch inputs.

Conditions for Clearing the DTC

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

Reference Information
Schematic Reference

Outside Rearview Mirror Schematics (Outside Rearview Mirror Schematics)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Outside Mirror Description and Operation (Heated Mirrors) (Outside Mirror Description and Operation (Heated Mirrors))Outside Mirror Description and Operation (Power Mirrors) (Outside Mirror Description and Operation (Power Mirrors))
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning) 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 X5 harness connector at the DDM.
2. Ignition ON, verify the scan tool Mirror Motor parameter is Idle.

• If not the specified value, replace the DDM.

3. Ignition OFF, connect the X5 harness connector at the DDM.
4. Ignition ON, observe the scan tool Mirror Motor parameter while cycling the mirror directional switch between the up, down, left and right positions. The parameter should change between Idle, Up, Down, Left, and Right.

• If the parameter does not cycle between the specified values, replace the outside rearview mirror switch.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Power Mirror Switch Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for DDM or PDM replacement, setup, and programming