GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2002 🢒 DeVille 🢒 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 lock actuator control circuit of one of the rear doors shorted to ground. This condition could open the RRDR MDL fuse located in the rear fuse block and simultaneously set DTCs U1162 and U1163 when the rear door lock actuator is actuated.

    2.

  2. This step checks to see that the door module associated with the inoperative door lock recognizes the switch inputs.

    Turning ON the headlamps in this step eliminates the possibility of the inoperative door lock switch finding an alternative path to ground through the switch illumination circuit, which could result in the scan tool displaying incorrect lock switch states.

    3.

  3. This step determines if the lock switch or lock switch circuits are the cause of the malfunction.

    If the 3-amp jumper wire fuse opens when the jumper wire is connected, test the appropriate switch signal circuits for a short to battery positive voltage.

  4. This step determines if the unlock circuit may be the cause of the malfunction.

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

    5.

  5. This step determines if the lock circuit may be the cause of the malfunction.

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

    6.

  6. 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.

    7.

  7. 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

DEFINITION: This test assumes that all DTCs have been diagnosed.

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 Description and Operation?

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

Go to Step 3

3

  1. Install a scan tool.
  2. Close all of the vehicles doors.
  3. Turn ON the ignition, with the engine OFF.
  4. Operate both front door lock switches to both the Lock and Unlock positions.
  5. Operate both rear door lock switches to the Lock position.

Did DTCs U1162 and U1163 simultaneously set current when you operated the lock switches?

Go to Step 14

Go to Step 4

4

  1. Turn ON the headlamps.
  2. Operate the lock switch of the door that is inoperative to both the Lock and Unlock positions.
  3. With the scan tool, observe the Door Lock Switch parameter in the appropriate Door Module, Inputs list. For the driver door lock switch, this would be the Door Lock Switch parameter in the Driver Door Switch, Inputs list.

Did the parameter change to both the Lock and Unlock states for a front door switch and (w/V4U) a rear door switch, or, (w/o V4U) the Lock state only for a rear door switch?

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 a good ground. For an inoperative rear door (w/o V4U), you would connect the jumper only between the lock signal circuit and a good 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, or, for the rear door of a vehicle w/o V4U, Lock only?

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 appropriate 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 harness connector of the inoperative door lock actuator.
  2. Connect a test lamp between the Unlock circuit of the harness connector and a good ground.
  3. Operate either one of the front door lock switches to Unlock.

Does the test lamp flash once upon operating the switch to UNLOCK?

Go to Step 8

Go to Step 11

8

  1. Connect a test lamp between the Lock circuit of the harness connector and a good ground.
  2. Operate either one of the front door lock switches to Lock.

Does the test lamp flash once upon operating the switch to LOCK?

Go to Step 9

Go to Step 11

9
  1. Connect a test lamp between the Unlock circuit and the Lock circuit of the harness connector.
  2. Operate either one of the front door lock switches to both Lock and Unlock.

Does the test lamp flash once upon operating the switch to LOCK and once upon operating the switch to 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 lock switch may need to be replaced.

Test the appropriate signal and ground circuits of the door lock switch 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 control circuits of the door lock actuator 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 control circuits of the door lock actuator for a short to 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 appropriate module logic ground circuit of the C1 connector 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 control circuits of both rear door lock actuators 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

Go to Step 18

15

Inspect for poor connections at the harness connector of the appropriate door lock switch. 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 harness connector of the appropriate passenger door module, or, if the inoperative lock is the driver door lock, at the harness connector of the driver door switch assembly (DDSA). 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 appropriate passenger door module or driver 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 connections 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 ground circuit of the appropriate door lock switch. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 24

--

20

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

Did you complete the replacement?

Go to Step 24

--

21

Replace the appropriate passenger door module, or, if the inoperative lock is the driver door lock, replace the driver door switch assembly (DDSA). Refer to Door Control Module Replacement or Front Door Switch Replacement .

Did you complete the replacement?

Go to Step 24

--

22

Replace the appropriate passenger door module or driver door module. Refer to Door Control Module Replacement .

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