GM Service Manual Online
For 1990-2009 cars only

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

  1. This step will test the express open feature and if the feature is operating properly, then inspect the limit switch low reference circuit for a poor condition or intermittent.

Step

Action

Value(s)

Yes

No

Schematic Reference: Sunroof Schematics

DEFINITION: Express open feature is disabled.

1

Did you perform the Diagnostic System Check - Power Sunroof?

--

Go to Step 2

Go to Diagnostic System Check - Power Sunroof

2

Operate the power sunroof express open feature.

Does the system operate normally?

--

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

  1. Turn the ignition ON, with the engine OFF.
  2. Measure the voltage between the limit switch low reference circuit at the sunroof module connector and B+.

Does the voltage measure near the specified value?

B+

Go to Step 5

Go to Step 4

4

Inspect for a poor connection in the sunroof limit switch low reference circuit at the sunroof module. 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 9

Go to Step 8

5

Test the limit switch low reference circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 9

Go to Step 6

6

Inspect for a poor connection in the sunroof limit switch low reference circuit at the position encoding system (PES) module. 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 9

Go to Step 7

7

Replace the PES module. Refer to Sunroof Position Encoding System Switch Replacement .

Did you complete the replacement?

--

Go to Step 9

--

8

Replace the sunroof module. Refer to Power Sunroof Express Module Replacement .

Did you complete the replacement?

--

Go to Step 9

--

9

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 3