GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Was the Data Link Communications System Check performed?

--

Go to Step 2

Go to Data Link Communications System Check

2

  1. Inspect the data link connector (DLC) and repair any damaged terminals if required.
  2. Verify that the Scan Tool is firmly connected to the DLC.
  3. Turn the ignition to the RUN position.
  4. Attempt scan tool communications with the powertrain control module (PCM).

Can communications be established?

--

System OK

Go to Step 3

3

  1. Turn the ignition switch to the OFF postion.
  2. Disconnect the powertrain control module (PCM) connector C 2.
  3. Disconnect the electronic brake control module (EBCM) connector C 1.
  4. Connect a J 39200 DMM on the data link connector (DLC) from terminal 2 to terminal 4.
  5. Measure the resistance.

Is the resistance greater than the specified value?

10M ohms

Go to Step 5

Go to Step 4

4

Locate and repair the short to ground in CKT 1807 (PPL).

Is the repair complete?

--

System OK

--

5

  1. Connect a J 39200 DMM from the DLC terminal 16 to terminal 2.
  2. Measure the voltage.

Is the voltage greater than the specified value?

1.0 V

Go to Step 6

Go to Step 7

6

Locate and repair the short to B + in CKT 1807 (PPL).

Is the repair complete?

--

System OK

--

7

  1. Connect a J 39200 DMM from the DLC terminal 2 to the PCM connector C 2, cavity 58.
  2. Measure the resistance.

Is the resistance greater than the specified value?

1.0 ohms

Go to Step 8

Go to Step 9

8

Locate and repair the open in CKT 1807.

Is the repair complete?

--

System OK

--

9

  1. Connect the EBCM.
  2. Connect the PCM.
  3. Turn the ignition switch to the RUN position.
  4. Install the scan tool.
  5. Attempt to establish communications with the PCM.

Can communications be established?

--

System OK

Go to Step 1