GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The power roof module (PRM) has a high and low power feed . The low power feed, battery 1, is used to provide power for the roof module logic and internal driver operation. The high power feed, battery 2, is used to provide power for the roof motor which draws higher amounts of current. The roof module monitors the voltage level at battery 1 and battery 2 to determine if the voltage level is out of range. If the voltage level is out of range, a DTC is set.

DTC Descriptors

This diagnostic procedure supports the following DTCs:

    • DTC B1325 Device Power 1 Circuit
    • DTC B1335 Device Power 3 Circuit

Conditions for Setting the DTC

    • The PRM detects battery 1 or battery 2 voltage range under 9 volts or over 16 volts.
    • The condition must be present for greater than 2 seconds.

Action Taken When the DTC Sets

    • Stores a current DTC B1325 or B1335 in the PRM memory
    • Stores a history DTC B1325 or B1335 in the PRM memory

Conditions for Clearing the DTC

    • The PRM no longer detects battery 1 or battery 2 voltage below 9 volts or higher than 16 volts for greater than 2 seconds.
    • The DTC is cleared using a scan tool.

Diagnostic Aids

    • The following conditions may cause an intermittent malfunction:
       - The battery voltage is out of range.
       - A charging system malfunction.
    • If the DTC does not reset after the code is cleared, then the problem may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This test verifies if the vehicle's starting/charging system is functioning properly.

  2. This test verifies if the PRM is functioning properly.

Step

Action

Value(s)

Yes

No

Schematic Reference: Sunroof Schematics

Connector End View Reference: Power Roof Systems Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

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Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

Verify that the vehicles starting/charging system is operating properly.

Is the starting/charging system operating properly?

--

Go to Step 3

Go to Symptoms - Engine Electrical in Engine Electrical

3

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the Battery 1 and Battery 2 parameters in the power roof module data list.

Does the scan tool indicate that the Battery 1 and the Battery 2 parameters are within the specified range?

8.5-16.3 V

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

Go to Step 4

4

Inspect for poor connections at the harness connectors of the power roof module (PRM). 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 6

Go to Step 5

5

Replace the PRM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

--

Go to Step 6

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6

  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK