GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Saturn 🢒 2003 🢒 ION 🢒 Engine 🢒 Engine Cooling 🢒 Diagnostic System Check - Engine Cooling

Test Description

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

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

    2.

  2. The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed.

Step

Action

Yes

No

1

Install a scan tool.

Does the scan tool power up?

Go to Step 2

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

2

  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 3

Go to Scan Tool Does Not Communicate with Class 2 Device or Scan Tool Does Not Communicate with CAN Device in Data Link Communications

3

Select the ECM. Display DTCs function on the scan tool.

Does the scan tool display any DTCs?

Go to Step 4

Go to Symptoms - Engine Cooling

4

Does the scan tool display any DTCs which begin with a "U"?

Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications

Go to Diagnostic Trouble Code (DTC) List