GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2005 🢒 DeVille 🢒 Body 🢒 Doors 🢒 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 (PFDM) determine the vertical position of the mirrors based on the signal voltage from these sensors.

DTC Descriptor

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 PFDM 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 voltage range 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 failed voltage range limits are for your particular vehicle/module.

If the Mirror 5-volt reference voltage indicated on the scan tool 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 volts

0-0.60 volts

4.7-5.0 volts

4.4 volts

0-0.53 volts

4.1-4.4 volts

3.8 volts

0-0.45 volts

3.6-3.8 volts

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 Mirrors 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 Mirrors option, refer to Body Control Module (BCM) Programming/RPO Configuration in Computer/Integrating Systems, to deactivate the option.
    • After readjusting the mirror positions, be sure to reset the mirror memory switch to the new 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.

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 Mirrors 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 12

--

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 value?

0.25-5.0 V

Go to Step 12

Go to Step 5

5
  1. Turn OFF the ignition.
  2. Disconnect the C5 harness connector from the door module that is associated with the inoperative mirror.
  3. Turn ON the ignition, with the engine OFF.
  4. With the scan tool, observe the Up/Down Sensor parameter in the Data list.

Does the scan tool indicate the voltage is greater than the specified value?

3.6 V

Go to Step 6

Go to Step 9

6
  1. Connect a 3-amp fused jumper between the vertical position sensor signal circuit and the low reference circuit at the door module pins.
  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 value?

0-0.75 V

Go to Step 7

Go to Step 9

7

Measure the voltage of the 5-volt reference circuit at the door module pin.

Does the voltage measure within the specified value?

3.50-5.00 V

Go to Step 8

Go to Step 9

8

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 12

Go to Step 10

9

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 12

Go to Step 11

10

Replace the inoperative mirror . Refer to Power Mirror Replacement .

Did you complete the replacement?

--

Go to Step 12

--

11

Replace the inoperative door module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

--

Go to Step 12

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12
  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