GM Service Manual Online
For 1990-2009 cars only

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 B1580: Mirror Horizontal Position Sensor Circuit

DTC B1590: Mirror Vertical Position Sensor Circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

5-Volt Reference

B1580, B1590

B1580, B1590

B1580, B1590

--

Driver/Passenger Mirror Horizontal Position Sensor Signal

B1580

B1580

B1580

--

Driver/Passenger Mirror Vertical Position Sensor Signal

B1590

B1590

B1590

--

Low Reference

B1580, B1590

B1580, B1590

B1580, B1590

--

Circuit/System Description

The Driver Door Module (DDM) and Passenger Door Module (PDM) determine the position of the outside rearview mirrors based on inputs from two mirror position sensors, one for vertical position, the other for horizontal position. Five volts are applied to each sensor through a shared 5-volt reference circuit and a shared low reference circuit supplies ground. Each sensor has an individual signal circuit which provides position voltage to the DDM/PDM.

Conditions for Running the DTC

Battery voltage must be between 9-16 volts.

Conditions for Setting the DTC

B1580

An improper voltage level is seen on the Driver/Passenger Mirror Horizontal Position Sensor Signal circuit.

B1590

An improper voltage level is seen the Driver/Passenger Mirror Vertical Position Sensor Signal circuit.

Action Taken When the DTC Sets

Memory recall functions 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 malfunction-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

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool References

Control Module References for scan tool information.

Circuit/System Verification

Ignition ON, observe the scan tool Mirror Horizontal Position and Mirror Vertical Position parameters. The reading should be between 0.2-4.8 volts and change as the mirror is moved, left, right, up, and down.

Circuit/System Testing

  1. Ignition OFF, disconnect the X7 harness connector at the appropriate door module.
  2. Ignition ON, verify a test lamp does not illuminate between the following circuit terminals and ground:
  3. • 5-volt reference circuit terminal 7
    • Signal circuit terminal 4
    • Signal circuit terminal 5
    • Low reference circuit terminal 10
    If the test lamp illuminates, test the appropriate circuit for a short to voltage.
  4. Ignition OFF, test for infinite resistance between the following circuits and ground:
  5. • 5-volt reference circuit terminal 7
    • Signal circuit terminal 4
    • Signal circuit terminal 5
    • Low reference circuit terminal 10
    If less than the specified value, test the appropriate circuit for a short to ground.
  6. Test for 4K-7K ohms between the 5-volt reference circuit terminal 7 and the low reference circuit terminal 10.
  7. If not within the specified range, test the 5-volt reference circuit and the low reference circuit for an open/high resistance. If the circuits test normal, test or replace the rearview mirror motor.
  8. Test for 1K-7K ohms between the 5-volt reference circuit terminal 7 and the signal circuit terminal 4.
  9. If not within the specified range, test the signal circuit for an open/high resistance. If the circuits test normal, test or replace the rearview mirror motor.
  10. Test for 1K-7K ohms between the 5-volt reference circuit terminal 7 and the signal circuit terminal 5.
  11. If not within the specified range, test the signal circuit for an open/high resistance. If the circuits test normal, test or replace the rearview mirror motor.
  12. If all circuits test normal, replace the door module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Outside Rearview Mirror Replacement
    •  Control Module References for DDM or PDM replacement, setup, and programming