GM Service Manual Online
For 1990-2009 cars only

Test Description

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

  1. Lack of communication may be due to a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.

  2. This step determines if the engine control module (ECM) has set any DTCs related to the HVAC system.

Step

Action

Yes

No

1

Did you review the HVAC Preliminary Checks in Heating, Ventilation, and Air Conditioning?

Go to Step 2

Go to HVAC Preliminary Checks in Heating, Ventilation and Air Conditioning

2

Install a scan tool.

Does the scan tool power up?

Go to Step 3

Go to Scan Tool Does Not Power Up in Data Link Communications

3

  1. Turn ON the ignition, with the engine OFF.
  2. Attempt to establish communication with the engine control module (ECM).

Does the scan tool communicate with the ECM?

Go to Step 4

Go to Scan Tool Does Not Communicate with Component in Data Link Communications

4

Select the display DTCs function on the scan tool for the ECM.

Does the scan tool display DTC P0532 or P0533?

Go to Diagnostic Trouble Code (DTC) List

Go to Step 5

5

Does the scan tool display any other DTCs?

Go to

    •  Diagnostic Trouble Code (DTC) List in Engine Controls - 0.8L (LBF)
    •  Diagnostic Trouble Code (DTC) List in Engine Controls - 1.0L (L11)

Go to Symptoms - HVAC Systems - Manual