GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

Important: A short to ground will cause an open fuse(s). Before performing this diagnostic procedure, inspect the fuse(s) for an open.

1

Was the system check performed?

--

Go to Step 2

Go to Power Door Locks System Check

2

Perform the body control module (BCM) diagnostic system check.

Are any door lock DTCs present?

--

Go to Body Control Module System Check

Go to Step 3

3

  1. Connect a scan tool to the data link connector (DLC).
  2. Monitor the BCM door unlock relay output while activating the door lock switch to the unlock position.

Does the output change from OFF to ON?

--

Go to Step 4

Go to Step 12

4

  1. Remove the unlock relay at the left IP junction block.
  2. Connect a test lamp to ground and use J 35616 .
  3. Frontprobe the left IP junction block unlock relay terminal 85 (CKT 194).
  4. Activate the door lock switch to the unlock position.

Does the test lamp light?

--

Go to Step 7

Go to Step 5

5

  1. Connect a test lamp to ground.
  2. Backprobe the left IP junction block connector C1 terminal F8.
  3. Activate the door lock switch to the unlock position.

Does the test lamp light?

--

Go to Step 6

Go to Step 9

6

Replace the left IP junction block.

Is the repair complete?

--

Go to Power Door Locks System Check

--

7

  1. Use J 39200 in order to measure resistance between the unlock relay terminal 86 CKT 150 and ground.
  2. Activate the door lock switch to the unlock position.

Does the measured resistance equal the specified value?

<1 ohms

Go to Step 8

Go to Step 6

8

Replace the door lock relay.

Is the repair complete?

--

Go to Power Door Locks System Check

--

9

  1. Connect a test lamp to ground.
  2. Backprobe the BCM connector C3 terminal B3.
  3. Activate the door lock switch to the UNLOCK position.

Does the test lamp light?

--

Go to Step 10

Go to Step 11

10

Repair the open or short to ground in CKT 194 between the BCM and the left IP junction block connector C1.

Is the repair complete?

--

Go to Power Door Locks System Check

--

11

  1. Inspect for a poor connection at the BCM connectors.
  2. Replace the BCM if there is no poor connection found at the BCM.

Is the repair complete?

--

Go to Power Door Locks System Check

--

12

  1. Use J 39200 connected to ground.
  2. Backprobe the BCM connector C2 terminal A2.

Does the measured voltage equal the specified value?

12--14V

Go to Step 13

Go to Step 11

13

  1. Use J 39200 connected to ground.
  2. Probe the BCM connector C2 terminal A2.
  3. Activate either lock switch to the UNLOCK position.

Does the DMM equal the specified value?

12--14V

Go to Power Door Locks System Check

Go to Step 14

14

Replace the lock switch(es) which did not pull voltage to 4-7 volts.

Is the repair complete?

--

Go to Power Door Locks System Check

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