GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Saturn 🢒 2003 🢒 ION 🢒 Body and Accessories 🢒 Wiring Systems 🢒 Diagnostic System Check - Engine Electrical

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 GM Lan circuit or due to a total malfunction of the class 2 serial data circuit or GM Lan circuit. The specified procedure will determine the particular condition.

    2.

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

    3.

  3. The symptom list in Symptoms will determine the correct diagnostic procedure to use.

    4.

  4. 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.

    5.

  5. 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

Perform the Battery Inspection/Test. Refer to Battery Inspection/Test .

Does the battery pass the test?

Go to Step 2

--

2
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.

Does the scan tool power up?

Go to Step 3

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

3

Important:  The engine may start during the following step. Turn OFF the engine as soon as you have observed the Crank power mode.

  1. With a scan tool, observe the Power Mode parameter in the Ignition data display of the the body control module (BCM).
  2. Rotate the ignition switch through all positions while observing the class 2 Power Mode parameter.

Does the ignition switch parameter reading match the ignition switch position for all switch positions?

Go to Step 5

Go to Power Mode Mismatch in Body Control System

4

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

Does the scan tool communicate with the ECM?

Go to Step 5

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

5

  1. Turn ON the ignition, with the engine OFF.
  2. Attempt to communicate with the BCM.

Does the scan tool communicate with the BCM?

Go to Step 6

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

6

  1. Select the Display DTCs function for the BCM and PCM.
  2. Record all of the displayed DTCs, the DTC status, and the module which set the DTC.

Does the scan tool display any DTCs?

Go to Step 7

Go to Symptoms - Engine Electrical

7

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

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

Go to Step 8

8

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

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

Go to Step 9

9

Does the scan tool display DTC B1000, B1001, B1004, B1007, or B1009?

Go to Diagnostic Trouble Code (DTC) List in Body Control System

Go to Diagnostic Trouble Code (DTC) List