GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you perform the Data Link Communications System Check?

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Go to Step 2

Go to Data Link Communications System Check

2

  1. Connect the scan tool to another vehicle of the same model and year in order to ensure proper operation of the scan tool.
  2. Turn the ignition switch to the RUN position.
  3. Attempt to establish communication with the Class 2 serial data line.

Does the scan tool communicate with the Class 2 serial data line?

--

Go to Step 4

Go to Step 3

3

The scan tool may be malfunctioning. Refer to the scan tool instruction manual in order to ensure that the scan tool is functioning.

Does the scan tool operate properly?

--

Go to Data Link Communications System Check

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4

  1. Connect the scan tool to the original vehicle.
  2. Verify that the scan tool connections are clean and tight.

Is the terminal contact between the data link connector (DLC) terminal 2 and the scan tool OK?

--

Go to Step 6

Go to Step 5

5

Repair the terminal contact between the DLC and the scan tool.

Did you complete the repair?

--

Go to Data Link Communications System Check

--

6

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the powertrain control module (PCM).
  3. Turn the ignition switch to the ON position.
  4. Attempt to establish communication with the remote function actuator (RFA) module.

Does the scan tool communicate with the RFA module?

--

Go to Step 7

Go to Step 8

7

Replace the PCM.

Did you complete the repair?

--

Go to Data Link Communications System Check

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8

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the RFA module.
  3. Test CKT 1807 (PPL) for an open, short to ground or battery positive voltage (B+).

Did you find the condition?

--

Go to Step 9

Go to Step 10

9

Repair the open or short in CKT 1807 (PPL).

Did you complete the repair?

--

Go to Data Link Communications System Check

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10

Replace the RFA module.

Did you complete the repair?

--

Go to Data Link Communications System Check

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