GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2004 🢒 XLR 🢒 Vehicle Control Systems 🢒 Vehicle DTC Information 🢒 DTC B1600 or B1605

Circuit Description

The driver door module (DDM) and the passenger door module (PDM) each provide motor control output functions for their respective mirrors . These output controls allow each door module to command their respective power mirrors in horizontal and vertical positions. The DDS sends a serial data message to the door modules when the mirror switch is activated to the up, down, left or right positions. When the door modules detect an active mirror command from the DDS, they will command the respective mirror motor in the appropriate direction. Each door module commands their respective mirror motors by applying a ground or voltage to the control circuit, depending on the desired mirror position. If the DDM or PDM detects a short to ground or voltage condition in a mirror motor control circuit for greater than 2 seconds, a DTC is set.

    • DTC B1600 LF/Driver Mirror Motor 1 Circuit
    • DTC B1605 LF/Driver Mirror Motor 2 Circuit

Conditions for Setting the DTC
    • The DDM or PDM detects a short to ground or voltage condition in a mirror motor control circuit.
    • Condition must be present for 2 seconds.

Action Taken When the DTC Sets

Stores DTC B1600 or B1605 in DDM or PDM memory.

Conditions for Clearing the DTC
    • The DDM or PDM no longer detects a short to ground or voltage condition in a mirror motor control circuit for longer than 2 seconds, and:
    • The DTC is cleared using a scan tool.

Diagnostic Aids
    • The following conditions may cause an intermittent malfunction:
       - There is an intermittent short to ground or voltage in a mirror motor control circuit.
       - A mirror motor is shorted internally.
    • If the DTC does not reset after the code is cleared, then the problem may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Tests for proper operation of the outside rearview mirror.

    2.

  2. Tests for a shorted outside rearview mirror.

    3.

  3. Tests for a short to ground or voltage in the vertical mirror motor control circuits.

    4.

  4. Tests for a short to ground or voltage in the horizontal mirror motor control circuits.

Step

Action

Yes

No

Schematic Reference: Outside Rearview Mirror Schematics and Door Control Module Schematics

Connector End View Reference: Power Door Systems Connector End Views

1

Did you perform the Vehicle Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

Activate the mirror switch in the UP, DOWN, LEFT and RIGHT directions for the appropriate outside rearview mirror.

Does the outside rearview mirror operate in all directions?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

  1. Disconnect the appropriate outside rearview mirror.
  2. Install a scan tool.
  3. Turn ON the ignition, with the engine OFF.
  4. Observe the appropriate mirror motors command parameter in the appropriate door module data list.
  5. Activate the mirror switch in the UP, DOWN, LEFT and RIGHT directions.

Do all of the mirror motors command parameters change state?

Go to Step 7

Go to Step 4

4

Did the outside rearview mirror operate in the horizontal direction?

Go to Step 5

Go to Step 6

5

Test the appropriate vertical mirror motor control circuits for a short to ground or voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 8

6

Test the appropriate horizontal mirror motor control circuits for a short to ground or voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 8

7

Inspect for poor connections at the harness connector of the appropriate outside rearview mirror. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 9

8

Inspect for poor connections at the harness connector of the appropriate door module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 10

9

Replace the appropriate outside rearview mirror. Refer to Outside Rearview Mirror Replacement .

Did you complete the replacement?

Go to Step 11

--

10
  1. Perform the power window reinitialization procedure. Refer to Power Window Reinitialization
  2. Replace the appropriate door module. Refer to Door Control Module Replacement .

Did you complete the replacement?

Go to Step 11

--

11
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK