GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2003 🢒 Park Avenue 🢒 Body and Accessories 🢒 Doors 🢒 Power Door Locks Inoperative

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step determines if there is a rear door lock actuator control circuit shorted to ground. This condition could open the RDM fuse located in the rear fuse block and set a DTC U1162 current when the rear door lock actuator is actuated.

    2.

  2. This step determines if the door modules recognize the lock switch inputs. However, if the lock switch ground circuit has failed, the scan tool could still display switch inputs transitioning to Lock and Unlock as if there were no failure. This is due to the fact that the lock switch can find an alternate path to ground through the switch illumination circuit when the headlamps are turned off. By turning the headlamps on in this step, the possibility of overlooking an open lock switch ground circuit as the cause of the malfunction is eliminated.

    3.

  3. This step determines if the door lock actuator unlock control circuit is the cause of the malfunction.

    If the test lamp is already illuminated before operating the lock switch to unlock, test the door lock actuator unlock control circuit for a short to battery voltage.

    4.

  4. This step determines if the door lock actuator lock control circuit is the cause of the malfunction.

    If the test lamp is already illuminated before operating the lock switch to lock, test the door lock actuator lock control circuit for a short to battery voltage.

    5.

  5. This step directs you to, either inspect for poor connections at the passenger door module , or, at the driver door switch assembly as a pre-requisite to replacing the passenger door module or driver door switch assembly. This is because lock switch signals for the driver door are detected and processed by the driver door switch assembly, while lock switch signals for the passenger door are detected and processed by the passenger door module.

    6.

  6. This step directs you to, either replace the passenger door module or driver door switch assembly. This is because lock switch signals for the driver door are detected and processed by the driver door switch assembly, while lock switch signals for the passenger door are detected and processed by the passenger door module.

Step

Action

Yes

No

Schematic Reference: Door Lock/Indicator Schematics

1

Did you perform the Door Systems Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Door Systems

2

Verify that the Power Door Locks Inoperative complaint is present.

Does the Power Door Lock System operate as described in the Power Door Locks Description and Operation?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

Operate both of the door lock switches to both the LOCK and UNLOCK positions.

Did DTC U1162 set current when you operated the door lock switches?

Go to Step 14

Go to Step 4

4

  1. Turn OFF the ignition.
  2. Install a scan tool.
  3. Close all of the vehicles doors.
  4. Turn ON the ignition, with the engine OFF.
  5. Turn ON the headlamps switch.
  6. Operate both of the door lock switches to both the LOCK and UNLOCK positions.
  7. With the scan tool, observe both Door Lock Switch parameters in the Driver Door Module, Data Display, Inputs list.

Did the parameters change to both the LOCK and UNLOCK states for both switches?

Go to Step 7

Go to Step 5

5
  1. Turn OFF the ignition.
  2. Disconnect the appropriate door lock switch harness connector.
  3. Connect a 3 amp fused jumper wire between, first the lock signal circuit of the harness connector and a good ground, and then between the unlock signal circuit of the harness connector and ground.
  4. Turn ON the ignition, with the engine OFF.
  5. With the scan tool, observe the appropriate door lock switch parameter.

Did the parameter change state to, first the LOCK, and then the UNLOCK as expected?

Go to Step 6

Go to Step 10

6
  1. Turn OFF the ignition.
  2. Connect a 3 amp fused jumper wire between the lock signal circuit and the ground circuit of the door lock switch harness connector.
  3. Turn ON the ignition, with the engine OFF.
  4. With the scan tool, observe the appropriate door lock switch parameter.

Did the parameter change state to LOCK as expected?

Go to Step 15

Go to Step 19

7

  1. Disconnect the inoperative door lock actuator harness connector.
  2. Connect a test lamp between the door lock motor unlock circuit and ground.
  3. With the scan tool, command the door lock to UNLOCK.

Does the test lamp flash once upon commanding UNLOCK?

Go to Step 8

Go to Step 11

8

  1. Connect a test lamp between the door lock motor lock circuit and ground.
  2. With the scan tool, command the door lock to LOCK.

Does the test lamp flash once upon commanding LOCK?

Go to Step 9

Go to Step 11

9
  1. Connect a test lamp between the door lock motor unlock circuit and the door lock motor lock circuit of the harness connector.
  2. With the scan tool, command the door lock to both LOCK and UNLOCK.

Does the test lamp flash once upon commanding LOCK and once upon commanding UNLOCK?

Go to Step 18

Go to Step 13

10

Important: If a power door lock switch signal circuit is found to be shorted to battery positive voltage, the power door lock switch may need to be replaced also.

Test the appropriate door lock switch signal and ground circuits for shorts to each other, a short to battery, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 24

Go to Step 16

11

Test the door lock actuator control circuits for a short to ground or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 24

Go to Step 12

12

Test the door lock actuator control circuits for a short to battery positive voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 24

Go to Step 17

13

Test the inoperative door module ground circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 24

Go to Step 17

14

Test the door lock actuator control circuits of both rear doors for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 24

--

15

Inspect for poor connections at the inoperative door lock switch harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 24

Go to Step 20

16

Inspect for poor connections at the inoperative passenger door module harness connector or if the inoperative lock is the driver door lock, at the driver door switch assembly harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 24

Go to Step 21

17

Inspect for poor connections at the harness connector of the inoperative door module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 24

Go to Step 22

18

Inspect for poor connection at the harness connector of the inoperative door lock actuator. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 24

Go to Step 23

19

Repair the open in the switch ground circuit. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 24

--

20

Replace the inoperative door lock switch. Refer to Door Lock Switch Replacement .

Did you complete the replacement?

Go to Step 24

--

21

Replace the inoperative door module or if the inoperative lock is the driver door lock, replace the driver door switch assembly. Refer to Door Control Module Replacement - Front or Front Door Switch Replacement .

Did you complete the replacement?

Go to Step 24

--

22

Replace the inoperative passenger door module or driver door module. Refer to Door Control Module Replacement - Front .

Did you complete the replacement?

Go to Step 24

--

23

Replace the inoperative door lock actuator. Refer to Front Side Door Latch Replacement or Rear Side Door Latch Replacement .

Did you complete the replacement?

Go to Step 24

--

24

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2