GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2005 🢒 CTS 🢒 Accessories 🢒 Navigation Systems 🢒 DTC B1591

Circuit Description

The LH mirror and the RH mirror vertical position sensors are potentiometers. The driver door module (DDM) and the passenger door module (PDM) determine the vertical position of the mirrors based on the signal voltage from these sensors.

DTC Descriptors

This diagnostic procedure supports the following DTC:

DTC B1591 Mirror Vertical Position Sensor Circuit Range/Performance

Conditions for Running the DTC

The DDM and the PDM must be powered up.

Conditions for Setting the DTC

The code will be set when the signal voltage of the mirror vertical position sensor is above or below the range limits, within 10 percent, for 30 seconds in the requested position. The out of range voltage limits depend upon what the actual voltage of the 5-volt reference circuit is, and will vary from vehicle to vehicle and from module to module. Use the table below to determine what the out of range voltage limits are for your particular vehicle/module.

If the mirror 5-volt reference voltage is closest to:

The code will be set when the sensor signal voltage is:

The code will be set when the sensor signal voltage is:

5.0 V

0-0.60 V

4.7-5.0 V

4.4 V

0-0.53 V

4.1-4.4 V

3.8 V

0-0.45 V

3.6-3.8 V

Action Taken When the DTC Sets

Mirror vertical memory movements are disabled. Manual movements are not disabled.

Conditions for Clearing the DTC

When the door modules no longer sense the failure

Diagnostic Aids
    • If the Personalization Option in the dash integration module (DIM) is activated on a vehicle that does not have the A45 memory option, DTCs B1586 and B1591 will be erroneously set. If DTCs B1586 and B1591 are set on a vehicle that does not have the A45 memory option, refer to Dash Integration Module Programming and Setup in Programming and Setup to deactivate the option.
    • After readjusting the mirror positions, be sure to reset the memory switch to the new mirror positions.
    • If this DTC is set as a history DTC, but not as a current DTC, remove the fuse for the door module that set the DTC for 10 seconds, then reinstall it.
    • The mirror position sensors are part of the mirror motor pack assembly and are not serviced separately.

Test Description

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

  1. This step verifies the integrity of the mirror 5-volt reference circuit.

    2.

  2. This step verifies that the mirror position sensor low reference circuit is not open.

    3.

  3. This step verifies that the voltage applied by the door module to the vertical position sensor signal circuit is within the appropriate range. When the mirror motor harness connector is disconnected, the measured voltage should be 3.5-5 volts.

    4.

  4. This step verifies that the door module recognizes the vertical position sensor signal circuit voltage being pulled to ground.

Step

Action

Value(s)

Yes

No

Schematic Reference: Outside Rearview Mirror Schematics

Connector End View Reference: Power Door Systems Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

Is the vehicle equipped with the A45 memory option?

--

Go to Step 4

Go to Step 3

3
  1. Turn OFF the ignition.
  2. Install a scan tool.
  3. Turn ON the ignition, with the engine OFF.
  4. Navigate to the Personalization Option screen of the dash integration module (DIM).
  5. Follow the on-screen instructions to deactivate the Personalization Option.

Did you complete the deactivation?

--

Go to Step 19

Go to Dash Integration Module Programming and Setup in Programming and Setup

4
  1. Turn OFF the ignition.
  2. Install a scan tool.
  3. Turn ON the ignition, with the engine OFF.
  4. Using the mirror position adjustment switch, move the applicable mirror to the limits of the up and down positions.
  5. With the scan tool, observe the Up/Down Sensor parameter in the associated door modules data list.

Does the scan tool indicate that the voltage increases with the up adjustments and decreases with the down adjustments and is within the specified range?

0.25-5 V

Go to Step 19

Go to Step 5

5

  1. Turn OFF the ignition.
  2. Remove the mirror face of the inoperative mirror in order to access the mirror motor. Refer to Outside Rearview Mirror Glass Replacement .
  3. Remove the mirror motor and disconnect the mirror motor harness connector. Refer to Outside Rearview Mirror Motor Replacement .
  4. Turn ON the ignition, with the engine OFF.
  5. Measure the voltage between the 5-volt reference circuit of the harness connector and a good ground.

Was the measured voltage within the specified range?

3.5-5 V

Go to Step 6

Go to Step 10

6

Measure the voltage between the 5-volt reference circuit and the low reference circuit of the harness connector.

Was the measured voltage within the specified range?

3.5-5 V

Go to Step 7

Go to Step 14

7

Measure the voltage between the mirror vertical position sensor signal circuit and the low reference circuit of the harness connector.

Was the measured voltage within the specified range?

3.5-5 V

Go to Step 9

Go to Step 8

8

Was the measured voltage in step 7 less than specified range?

3.5-5 V

Go to Step 12

Go to Step 13

9

  1. Connect a 3-amp fused jumper wire between the vertical position sensor signal circuit and the low reference circuit of the harness connector.
  2. With the scan tool, observe the Up/Down Sensor parameter in the applicable door module data list.

Does the scan tool indicate the voltage is within the specified range?

0-0.75 V

Go to Step 15

Go to Step 16

10

Test the 5-volt reference circuit for an open or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 19

Go to Step 11

11

Test the 5-volt reference circuit for a short to voltage or a short to any other circuit in the harness connector. Refer to Circuit Testing and Wiring Repairs in Wiring System.

Did you find and correct the condition?

--

Go to Step 19

Go to Step 16

12

Test the vertical position sensor signal circuit for a short to ground, an open, or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 19

Go to Step 16

13

Test the vertical position sensor signal circuit for a short to voltage or a short to any other circuit in the harness connector. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 19

Go to Step 16

14

Test the low reference circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 19

Go to Step 16

15

Inspect for poor connections at the harness connector of the inoperative mirror motor. 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 19

Go to Step 17

16

Inspect for poor connections at the C5 harness connector of the door module associated with the inoperative 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 19

Go to Step 18

17

Replace the inoperative mirror motor. Refer to Outside Rearview Mirror Motor Replacement .

Did you complete the replacement?

--

Go to Step 19

--

18

Important: Perform the setup procedure for the replacement door module. Refer to Door Control Module Programming and Setup in Programming and Setup.

Replace the door module. Refer to Control Module References in Computer/Integrating Systems.

Did you complete the replacement?

--

Go to Step 19

--

19
  1. Clear the DTCs using the scan tool.
  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