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Home >> Buick >> 2013 >> Regal L4-2.0L Turbo >> Repair and Diagnosis >> Body and Frame >> Roof and Associated Components >> Sunroof / Moonroof >> Testing and Inspection >> Power Sunroof/Sunshade Malfunction

Power Sunroof/Sunshade Malfunction





Power Sunroof/Sunshade Malfunction

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.

Diagnostic Fault Information






Circuit/System Description

The sunroof electrical system uses a master/slave configuration utilizing a serial data based system for communication. The body control module (BCM) is designated as the master, while the sunroof motor module is configured as the slave.

As the system master, the BCM uses serial data communication bus to enable or disable sunroof operation, communicate vehicle information to the sunroof motor, and request sunroof movement. The sunroof controller provide system status and diagnostic information to the BCM for diagnostic reporting and operational purposes. The control switches places a different resistor ladder network in the circuit depending on the function selected. The sunroof motor analog to digital switch input reads the resulting voltage range and determines the function.

Reference Information

Schematic Reference

Sunroof Schematics [1][2]Electrical Diagrams

Connector End View Reference

Component Connector End Views Sunshade - Left

Description and Operation

Sunroof Description and Operation (Tilt and Slide System) Description and Operation

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 Control Module References for scan tool information

Circuit/System Verification

1. Ignition ON.

2. Verify the sunroof opens and closes when pressing the open and close sunroof switch.

• If the sunroof does not open or close
Refer to Circuit/System Testing.

• If the sunroof opens and closes

3. Verify the sunroof opens and closes to the vent position when pressing the open and close sunroof vent switch.

• If the sunroof does not open or close to the vent position
Refer to Circuit/System Testing.

• If the sunroof opens and closes to the vent position

4. All OK.

Circuit/System Testing

Note: Because of the accessibility of the switches, perform the switch component testing before beginning the circuit/system testing.

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the M69 Sunroof Motor. It may take up to 2 minutes for all vehicle systems to power down.

2. Test for less than 10 ohms between the ground circuit terminal 2 and ground.

• If 10 ohms or greater

1. Ignition OFF, disconnect the harness connector at the M69 Sunroof Motor.

2. Test for less than 2 ohms in the ground circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, repair the open/high resistance in the ground connection.

• If less than 10 ohms

3. Verify a test lamp illuminates between the B+ circuit terminal 1 and ground.

• If test lamp does not illuminate and the circuit fuse is good

1. Ignition OFF.

2. Test for less than 2 ohms in the B+ circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse.

• If the test lamp does not illuminate and the circuit fuse is open

1. Ignition OFF.

2. Test for infinite resistance between the B+ circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.

• If infinite resistance, replace the M69 Sunroof Motor.

• If the test lamp illuminates

4. Ignition ON.

5. Test for less than 1 V between the signal circuit terminals listed below and ground:

* Terminal 3 - M69 Sunroof Motor

* Terminal 5 - M69 Sunroof Motor

* Terminal 6 - M69 Sunroof Motor

• If 1 V or greater
Repair the short to voltage on the signal circuit.

• If less than 1 V

6. Ignition OFF.

7. Test for infinite resistance between the signal circuit terminals listed below and ground:

* Terminal 3 - M69 Sunroof Motor

* Terminal 5 - M69 Sunroof Motor

* Terminal 6 - M69 Sunroof Motor

• If less than infinite resistance
Repair the short to ground on the signal circuit

• If infinite resistance

8. Disconnect the harness connector at the S72 Sunroof Switch and the S88 Sunroof Tilt Switch.

9. Test for less than 5 ohms between the circuit terminals listed below:

* S72 Sunroof Switch terminal 1 and M69 Sunroof Motor terminal 3

* S72 Sunroof Switch terminal 4 and M69 Sunroof Motor terminal 5

* S88 Sunroof Tilt Switch terminal 1 and M69 Sunroof Motor terminal 3

* S88 Sunroof Tilt Switch terminal 4 and M69 Sunroof Motor terminal 6

• If greater than 5 ohms
Repair the open/high resistance in the circuit.

• If less than 5 ohms

10. Test or replace the M69 Sunroof Motor.

Component Testing

Sunroof Switch

Static Test

1. Ignition OFF, disconnect the harness connector at the S72 Sunroof Switch.

2. Test for 5.4-6.6k ohms between the control terminal 4 and the low reference terminal 1.

• If not between 5.4-6.6k ohms
Replace the S72 Sunroof Switch.

• If between 5.4-6.6k ohms

3. Test for 234-286 ohms between the control terminal 4 and the low reference terminal 1 while pressing the open switch while pressing the open switch.

• If not between 234-286 ohms
Replace the S72 Sunroof Switch.

• If between 234-286 ohms

4. Test for 76-93 ohms between the control terminal 4 and the low reference terminal 1 while pressing the express open switch.

• If not between 76-93 ohms
Replace the S72 Sunroof Switch.

• If between 76-93 ohms

5. Test for 1.3-1.5k ohms between the control terminal 4 and the low reference terminal 1 while pressing the close switch.

• If not between 1.3-1.5k ohms
Replace the S72 Sunroof Switch.

• If between 1.3-1.5k ohms

6. Test for 540-660 ohms between the control terminal 4 and the low reference terminal 1 while pressing the express close switch.

• If not between 540-660 ohms
Replace the S72 Sunroof Switch.

• If between 540-660 ohms

7. All OK

Sunroof Tilt Switch

Static Test

1. Ignition OFF, disconnect the harness connector at the S88 Sunroof Tilt Switch.

2. Test for 5.0-6.2k ohms between the control terminal 4 and the low reference terminal 1.

• If not between 5.0-6.2k ohms
Replace the S88 Sunroof Tilt Switch.

• If between 5.0-6.2k ohms

3. Test for 329-402 ohms between the control terminal 4 and the low reference terminal 1 while pressing the open switch.

• If not between 329-402 ohms
Replace the S88 Sunroof Tilt Switch.

• If between 329-402 ohms

4. Test for 872-1065 ohms between the control terminal 4 and the ground terminal 1 while pressing the close switch.

• If not between 872-1065 ohms
Replace the S88 Sunroof Tilt Switch.

• If between 872-1065 ohms

5. All OK

Repair Instructions

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

* Sunroof Switch Replacement Service and Repair

* Control Module References Control Module References for sunroof actuator replacement, programming and setup

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