For 1990-2009 cars

### 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.

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
B+ | 1 | 1 | -- | --
Sunroof Switch Close Signal | 1 | 1 | 1 | --
Sunroof Switch Open Signal | 1 | 1 | 1 | --
Sunroof Vent Switch Open Signal | 1 | 1 | 1 | --
Sunroof Vent Switch Close Signal | 1 | 1 | 1 | --
Sunroof Switch Ground | -- | 1 | -- | --
Sunroof Module Ground | -- | 1 | -- | --
1. Power Sunroof Malfunction

### Circuit/System Description

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

As the system master, the BCM uses the LIN-Bus communication bus to enable or disable sunroof operation, communicate vehicle information to each controller, 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 controllers analog to digital switch input reads the resulting voltage range and determines the function

### Reference Information

#### Schematic Reference

Sunroof Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Sunroof Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

#### Sunroof

Ignition ON, press the sunroof switch to the open and close positions. The sunroof should open and close when changing between the commanded states.

#### Ventilation

Ignition ON, press the sunroof ventilation switch to the open and close positions. The sunroof should move up and down when changing between the commanded states.

### 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, disconnect the harness connector at the K61 Sunroof Control Module.
2. Test for less than 5 Ω between the low reference circuit terminal 2 and ground.

⇒ | If greater than the specified value, test the ground circuit for an open/high resistance.

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

⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, determine if the K61 Sunroof Control Module is causing the fuse to open. Replace the K61 Sunroof Control Module.

4. Ignition ON, verify that a test lamp does not illuminate between the circuit terminal 3, terminal 6 and ground.

⇒ | If the test lamp does illuminate, test the appropriate circuit for a short to voltage.

5. Ignition OFF, verify that a test lamp does not illuminate between the circuit terminal 3, terminal 6 and B+.

⇒ | If the test lamp does illuminate, test the appropriate circuit for a short to voltage. If the test lamp does not illuminate, test the appropriate circuit for a open/high resistance.

6. If all circuits test normal, test or replace the K61 Sunroof Control Module.

### Component Testing

#### Sunroof Switch

#### Static Test

1. Ignition OFF, disconnect the harness connector at the S72 Sunroof Switch.
2. Test for 460-480 kΩ between the switch terminals 1 and 4.

⇒ | If not within the specified range, replace the S72 Sunroof Switch.

3. Test for 230-250 Ω between the signal terminal 1 and the low reference circuit terminal 4 while pressing the open switch.

⇒ | If not within the specified range, replace the S72 Sunroof Switch.

4. Test for 75-95 Ω between the signal terminal 1 and the low reference circuit terminal 4 while pressing the express open switch.

⇒ | If not within the specified range, replace the S72 Sunroof Switch.

5. Test for 410-430 Ω between the signal terminal 1 and the low reference circuit terminal 4 while pressing the close switch.

⇒ | If not within the specified range, replace the S72 Sunroof Switch.

6. Test for 330-350 Ω between the signal terminal 1 and the low reference circuit terminal 4 while pressing the express close switch.

⇒ | If not within the specified range, replace the S72 Sunroof Switch.

#### Sunroof Ventilation Switch

#### Static Test

1. Ignition OFF, disconnect the harness connector at the S88 Sunroof Ventilation Switch.
2. Test for 460-480 kΩ between the switch terminals 1 and 4.

⇒ | If not within the specified range, replace the S88 Sunroof Ventilation Switch.

3. Test for 230-250 Ω between the signal terminal 1 and the low reference circuit terminal 4 while pressing the open switch.

⇒ | If not within the specified range, replace the S88 Sunroof Ventilation Switch.

4. Test for 410-430 Ω between the signal terminal 1 and the low reference circuit terminal 4 while pressing the close switch.

⇒ | If not within the specified range, replace the S88 Sunroof Ventilation Switch.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Sunroof Module Assembly Replacement

• | Control Module References for sunroof motor/actuator replacement, setup, and programming