GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you perform the Data Link Connector (DLC) System Check?

--

Go to Step 2

Refer to DLC System Check

2

Is the scan tool properly configured to interface with this vehicle?

--

Go to Step 3

Go to Step 7

3

  1. Connect the scan tool on a known good vehicle.
  2. Perform the DLC system check on a known good vehicle.

Does the scan tool communicate with the known good vehicle?

--

Go to Step 4

Go to Step 7

4

  1. Turn the ignition switch to the LOCK position.
  2. Disconnect SP205.
  3. Use a DMM in order to measure the voltage between DLC terminal 2 and B+.

Is the voltage measured within the specified range?

9-14 V

Go to Step 11

Go to Step 5

5

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

Is the voltage less than the specified value?

2 V

Go to Step 6

Go to Step 12

6

Use a DMM in order to check continuity between DLC terminal 2 and SP205 harness connector terminal A.

Is there continuity?

--

Go to Step 8

Go to Step 13

7

Refer to the scan tool manufacturer and/or the scan tool user's manual for the correct operation of the scan tool.

Has the repair been made?

--

Go to DLC System Check

--

8

  1. Turn the ignition switch to the LOCK position.
  2. Connect the Tech 2 to the DLC.
  3. Turn the ignition switch to the RUN position.
  4. Using a 15A fused jumper, jump between SP205 terminal A and each of SP205 terminals B, E, F, G, L, M one at a time.

Is communication established between each of the modules and the Tech 2?

--

Go to Step 9

Go to Step 10

9

Replace SP205.

Is the replacement complete?

--

Go to Step 18

--

10

Check for a short to ground in the module circuit that does not communicate with the Tech 2.

Is there a short to ground?

--

Go to Step 14

Go to Step 15

11

Repair the short to ground in circuit 1132.

Has the repair been made?

--

Go to Step 18

--

12

Repair the short to B+ in circuit 1132.

Has the repair been made?

--

Go to Step 18

--

13

Repair a poor connection or an open in circuit 1132.

Has the repair been made?

--

Go to Step 18

--

14

Repair the short to ground.

Has the repair been made?

--

Go to Step 18

--

15

Check for a short to B+.

Is there a short to B+?

--

Go to Step 16

Go to Step 17

16

Repair the short to B+.

Has the repair been made?

--

Go to Step 18

--

17

Replace the module that will not communicate.

Is the replacement complete?

--

Go to Step 18

--

18

  1. Turn the ignition switch to the LOCK position.
  2. Reconnect all connectors/components that have been disconnected.

Have all the repairs been made?

--

Go to DLC System Check

--