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?

--

Go to Step 2

Go to Data Link Communications System Check

2

Use a J 39200 Digital Multimeter (DMM) in order to measure the voltage between the Data Link Connector DLC terminal 16 and the ground.

Is the voltage within the specified range?

B+ (9-14 V)

Go to Step 3

Go to Step 13

3

Use a J 39200 DMM in order to measure the voltage between B+ and DLC terminal 5.

Is the voltage within the specified range?

B+ (9-14 V)

Go to Step 4

Go to Step 22

4

Use a J 39200 DMM in order to measure the voltage between B+ and DLC terminal 4.

Is the voltage within the specified range?

B+ (9-14 V)

Go to Step 5

Go to Step 23

5

Inspect for proper connection of the Scan Tool to the DLC.

Is the connection OK between the Scan Tool and the DLC?

--

Go to Step 6

Go to Step 11

6

Use the Scan Tool in order to establish communication with the PCM on a different vehicle.

Can communication be established with the Scan Tool ?

--

Go to Step 7

Go to Step 12

7

  1. Reconnect the Scan Tool to the DLC.
  2. Turn the ignition switch to the RUN position.
  3. Use a Scan Tool in order to establish communication with the Powertrain Control Module (PCM).

Can the Scan Tool communicate with the PCM?

--

Go to Step 14

Go to Step 8

8

  1. Turn the ignition switch to the LOCK position.
  2. Disconnect the PCM connector C1.
  3. Disconnect the SDM connector.
  4. Disconnect the EBCM connector C1.
  5. Use a J 39200 DMM in order to measure the resistance between the DLC terminal 9 and the DLC terminal 5.

Is the resistance the same as the specified value?

Go to Step 9

Go to Step 15

9

  1. Turn the ignition switch to the RUN position.
  2. Use a J 39200 DMM in order to measure the voltage between the DLC terminal 9 and the DLC terminal 5.

Is the voltage less than the specified value?

1 V

Go to Step 17

Go to Step 16

10

Repair the poor connection or an open in CKT 640 between the DLC terminal 16 and S202.

Is the repair complete?

--

Go to Step 18

--

11

Repair the poor connection between the DLC and the Scan Tool .

Is the repair complete?

--

Go to Step 18

--

12

Determine if the Scan Tool is malfunctioning.

Refer to the scan tool instruction manual for additional information.

Is the action complete?

--

Go to Step 18

--

13

Does the radio work?

--

Go to Step 10

Go to Step 19

14

Malfunction is not present or intermittent.

Inspect the PCM, SDM, and EBCM connectors for a poor connection, short to B+, or short to ground in CKT 800.

Repair as necessary.

Is the action complete?

--

Go to Step 18

--

15

Repair the short to ground in CKT 800.

Is the repair complete?

--

Go to Step 18

--

16

  1. Turn the ignition switch to the LOCK position.
  2. Repair the short to voltage in CKT 800.

--

Go to Step 18

--

17

Check continuity between DLC terminal 9 and the PCM connector C1 terminal 15.

Is there continuity?

--

Go to Step 25

Go to Step 26

18

  1. Ensure the ignition switch is in the LOCK position.
  2. Reinstall connectors/components removed.

Is the action complete?

--

Go to Data Link Communications System Check

--

19

Check Fuse 10.

Is Fuse 10 OK?

--

Go to Step 20

Go to Step 21

20

Repair a poor connection or open in CKT 640 between the fuse block and S202.

Has the repair been made?

--

Go to Step 18

--

21

Replace the fuse.

Is the repair complete?

--

Go to Step 18

--

22

Does the instrument cluster display work?

--

Go to Step 23

Go to Step 24

23

Repair a poor connection or open in CKT 1550 between the DLC and S211.

Has the repair been made?

--

Go to Step 18

--

24

Repair a poor connection or open in CKT 1550 between S211 and G201.

Has the repair been made?

--

Go to Step 18

--

25

  1. Reconnect the PCM connector C1.
  2. Check for a short to ground in CKT 800.

Is a short to ground present?

--

Go to Data Link Connector Diagnosis in Engine Controls 3.1

or

Data Link Connector Diagnosis in Engine Controls 3.8

Go to Step 27

26

Repair the poor connection or an open in CKT 800.

Is the repair complete?

--

Go to Step 18

--

27

  1. Reconnect the EBCM connector C1.
  2. Check for a short to ground in CKT 800.

Is a short to ground present?

--

Go to Diagnostic System Check in ABS

Go to SIR Diagnostic System Check in SIR