GM Service Manual Online
For 1990-2009 cars only

LH Door Lock Inoperative

Step

Action

Value(s)

Yes

No

DEFINITION: The LH door lock does not LOCK or UNLOCK from the LH door lock switch.

1

Were you sent here from the DCM Diagnostic System Check?

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Go to Step 2

Go to Power Windows System Check

2

Check if any of the following DTCs are stored in the LDCM as history:

    • DTC B2236
    • DTC B2238
    • DTC B2276

Are any of these DTCs stored as history?

--

Go to the Applicable Table

Go to Step 3

3

Check the LH door lock for mechanically malfunctions (binding or bent lock rod, obstructions, etc.).

Was a problem found and repaired?

--

Go to Step 14

Go to Step 4

4

Using a scan tool, select LDCM and command the LH door to LOCK and UNLOCK the LH door.

Does the LH door LOCK and UNLOCK?

--

Go to Step 6

Go to Step 5

5

  1. Turn OFF the ignition switch.
  2. Disconnect the LH door lock motor connector.
  3. Turn ON the ignition switch.
  4. At the LH door lock motor connector (harness side), connect a test light between terminals A and B.
  5. Using a scan tool, command the LH door to LOCK and UNLOCK the LH door.

Does the test light turn ON and OFF with each command?

--

Go to Step 11

Go to Step 8

6

  1. Using a scan tool, select LDCM inputs and monitor the LH door LOCK switch status.
  2. Press the LH door LOCK switch.

Does the scan tool display ACTIVE?

--

Go to Step 7

Go to Step 9

7

  1. Using a scan tool, select LDCM inputs and monitor the LH door UNLOCK switch status.
  2. Press the LH door UNLOCK switch.

Does the scan tool display ACTIVE?

--

System OK

Go to Step 10

8

Check for an open or short to ground in CKT 294 or CKT 295.

Was a problem found and repaired?

--

Go to Step 14

Go to Step 12

9

Check for an open in CKT 781 or CKT 150.

Was a problem found and repaired?

--

Go to Step 14

Go to Step 13

10

Check for an open in CKT 780 or CKT 150.

Was a problem found and repaired?

--

Go to Step 14

Go to Step 13

11

Replace the LH door lock motor. Refer to Door Lock Replacement .

Is the replacement complete?

 

Go to Step 14

--

12

  1. Replace the LDCM. Refer to Door Control Module Replacement .
  2. Program the replacement DCM (hardtop only). Refer to Door Control Module Programming/RPO Configuration .

Is the replacement complete?

--

Go to Step 14

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13

Replace the LH door switch assembly. Refer to Door Lock Switch Replacement .

Is the replacement complete?

--

Go to Step 14

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14

  1. Turn OFF the ignition switch.
  2. Reconnect or install any connectors or components that were disconnected or removed.
  3. Turn ON the ignition switch.
  4. Clear any DTCs. Refer to Diagnostic Trouble Code (DTC) Clearing .

Is the repair complete?

--

System OK

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