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Home >> Chevrolet >> 2008 >> Cobalt L4-2.4L >> Repair and Diagnosis >> Body and Frame >> Roof and Associated Components >> Sunroof / Moonroof >> Testing and Inspection >> Symptom Related Diagnostic Procedures >> Power Sunroof Malfunction

Power Sunroof Malfunction



Power Sunroof Malfunction

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information






Circuit/System Description

The sunroof motor/actuator supplies voltage to the contacts of the sunroof switch through the sunroof switch close signal circuit and the sunroof switch open signal circuit. When the switch is operated, the contacts and signal circuit for the selected mode are closed to ground, the voltage is pulled low in the sunroof motor/actuator, and the appropriate signal is recognized. The sunroof motor/actuator then internally applies battery positive voltage and ground to the appropriate circuits of the reversible power sunroof motor in order to move the sunroof glass panel to the open, close, or vent position.

Circuit/System Verification

1. With the sunroof in the closed position, press the sunroof vent switch. The sunroof should vent.
2. With the sunroof in the closed position, press the sunroof open switch. The sunroof should open.
3. With the sunroof in the open position, press the sunroof close switch. The sunroof should close.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the sunroof switch.
2. Ignition OFF, test for less than 5 ohms between the ground circuit terminal A and ground.

^ If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, verify a test lamp illuminates between the B+ circuit terminal E and ground.

^ If the test lamp does not illuminate, test the circuit for a short to ground or an open/high resistance.

4. Ignition OFF, connect the harness connector at the sunroof switch.
5. Disconnect the X302 inline harness connector at the sunroof motor.
6. Test for less than 5 ohms between the ground circuit terminal A and ground.
7. Connect a test lamp between the sunroof motor control circuit terminals C and D.
8. Ignition ON, cycle the sunroof switch between the OPEN and CLOSED positions. The test lamp should illuminate when switching between the commanded states.

^ If the test lamp remains OFF during any of the commanded state, test the control circuit terminal C and control circuit terminal D for a short to ground or an open/high resistance. If both circuits test normal, replace the sunroof switch.

9. Connect a test lamp between the control circuits terminals B and D.
10. Cycle the sunroof between the VENT to OFF positions. The test lamp should illuminate when in VENT position.

^ If the test lamp remains OFF during VENT, test the control circuit terminal B and control circuit terminal D for a short to ground or an open/high resistance. If both circuits test normal, replace the sunroof switch.

11. If all circuits test normal, test or replace the sunroof motor.

Component Testing

Sunroof Switch
1. Ignition OFF, disconnect the harness connector at the sunroof switch.
2. Test for infinite resistance between the following control circuits and the B+ circuit terminal E.

* Control circuit terminal A
* Control circuit terminal B
* Control circuit terminal C
* Control circuit terminal D

^ If less than the specified range, replace the sunroof switch.

3. While holding the sunroof switch button to OPEN, test for less than 1 ohms between the following circuits.

* Control circuit terminal A and C
* Control circuit terminal D and the B+ circuit terminal E

^ If greater than the specified range, replace the sunroof switch.

4. While holding the sunroof switch button to VENT, test for less than 1 ohms between the following circuits.

* Control circuit terminal D and the B+ circuit terminal E
* Control circuit terminal C and B

^ If greater than the specified range, replace the sunroof switch.

5. While holding the sunroof switch button to CLOSE, test for less than 1 ohms between the following circuits.

* Control circuit terminal A and D
* Control circuit terminal C and the B+ circuit terminal E

^ If greater than the specified range, replace the sunroof switch.

Sunroof Motor
1. Ignition OFF, disconnect the harness connector at the sunroof motor.
2. Install a 20-amp fused jumper wire between the control terminal 1 and 12 volts. Momentarily install a jumper wire between the control terminal 2 and ground. The window motor should OPEN or CLOSE.

^ If the function does not perform as specified, replace the sunroof motor.

3. Reverse the jumper wires. The sunroof motor should go in the opposite direction as step 2.

^ If the function does not perform as specified, replace the sunroof motor.

Repair Instructions

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

* Sunroof Motor/Actuator Replacement
* Sunroof Switch Replacement
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