GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2005 🢒 Park Avenue 🢒 Restraints 🢒 SIR 🢒 DTC U1161-U1163 or U1170

Circuit Description

The power door serial data line provides a means for information exchange among the vehicle door modules. Door module information on inputs and commanded outputs are converted to power door serial data for exchange among the door modules. The driver door module (DDM) periodically addresses each module on the power door serial data line. When a module does not respond to the DDM, the DTC for that module is set.

The DDM can also take information from other modules connected to the class 2 serial data circuit and relay the command to the power door serial data circuit. Vehicle power mode messages, ignition switch position, from the dash integration module (DIM) is an example.

DTC Descriptors

This diagnostic procedure supports the following DTCs:

    • DTC U1161 Loss of PDM Serial Data
    • DTC U1162 Loss of Rear Door Module Serial Data
    • DTC U1170 Loss of Driver Door Switch Assembly Serial Data

Conditions for Running the DTC
    • DTCs B1982 and B1983 do not have a current status.
    • The DDM has power.
    • The DDM has received an input or a class 2 wake-up message.

Conditions for Setting the DTC

When a response message from the passenger door module (PDM), the rear door module (RDM), or the driver door switch assembly (DDSA) is not received by the DDM within 2 seconds of the DDMs request, the DTC is set.

Conditions for Clearing the DTC
    • A current DTC will clear when a response message from the failed door module or DDSA is detected or at the end of the current ignition cycle.
    • A history DTC will clear upon receipt of a scan tool Clear DTCs command.

Test Description

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

  1. DTCs U1161, U1162, and U1170 set simultaneously indicate a total malfunction of the power door serial data circuit.

  2. When DTCs U1161 and U1162 set simultaneously, but U1170 does not set, the malfunction may be caused by an open in the power door serial data circuit between the DDM and the rear fuse block, or by an open in the ground circuit shared by the passenger front door module and the RDM, between splice S207 and the body ground terminal (G201).

    3.

  3. Loss of communications with individual modules may be due to an unpowered module. This step verifies that the module has a power supply.

    4.

  4. Loss of communication with individual modules may be due to an ungrounded module. This step verifies that the module has a ground supply.

    5.

  5. The power door serial data circuit is shorted to voltage or ground. The condition may be due to the wiring or due to a malfunction in one of the modules. When testing the wiring for a short, make sure there is not a module connected to the wire being tested.

    6.

  6. Operating the window and locks from the scan tool via the class 2 serial data circuit isolates the cause of the malfunction to the power door serial data circuit.

    7.

  7. The DDM has the capability of controlling the driver door functions. The malfunction must be due to the DDSA.

    8.

  8. The following steps isolate the door module which is preventing power door serial data communications.

    9.

  9. The open in the power door serial data circuit is between the DDM and the rear fuse block.

Step

Action

Yes

No

Schematic Reference: Door Control Module Schematics

Connector End View Reference: Master Electrical Component List in Wiring Systems

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

Did you record DTCs U1161, U1162, and U1170 all with a current status?

Go to Step 6

Go to Step 3

3

Did you record DTCs U1161 and U1162 all with a current status, but not U1170?

Go to Step 14

Go to Step 4

4

Important:: If the DTC set current is DTC U1170, you would test the battery positive voltage circuit of the driver door switch assembly (DDSA).

If the DTC set current is DTC U1162, you would test both battery positive voltage circuits associated with connector C1 of the rear door module (RDM).

Test the battery positive voltage circuit associated with connector C1 of the door module that is not communicating for an open or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 23

Go to Step 5

5

Important:: If the DTC set current is DTC U1170, you would test the ground circuit of the DDSA.

If the DTC set current is DTC U1162, you would test both ground circuits associated with connector C1 of the RDM.

  1. Turn OFF the ignition.
  2. Test the ground circuit associated with connector C1 of the door module that is not communicating for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 23

Go to Step 15

6

  1. Turn OFF the ignition.
  2. Disconnect the driver door module (DDM) and the DDSA.
  3. Test the power door serial data circuit between the DDM and DDSA for a short to ground or a short to voltage. Turn ON the ignition, with the engine OFF when you test 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 23

Go to Step 7

7
  1. Turn OFF the ignition.
  2. Disconnect the passenger door module (PDM) and the RDM.
  3. Test the power door serial data circuit for a short to ground or a short to voltage. Turn ON the ignition, with the engine OFF when you test 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 23

Go to Step 8

8

  1. Connect the DDM.
  2. Install a scan tool.
  3. Turn ON the ignition, with the engine OFF.
  4. Select the Special Functions for the DDM.
  5. Operate the driver door power window using the scan tool.
  6. Operate the driver door power lock using the scan tool.

Does the window or lock operate properly?

Go to Step 9

Go to Step 16

9

  1. Turn OFF the ignition.
  2. Connect the DDSA.
  3. Turn ON the ignition, with the engine OFF.
  4. Operate the driver door power window using the DDSA.
  5. Operate the driver door power lock using the DDSA.

Does the window or lock operate properly?

Go to Step 10

Go to Step 18

10

    Important: Operate the power window from the switch at the passenger door before using the switch at the driver door. The following procedure assumes the power window operates properly.

  1. Turn OFF the ignition.
  2. Connect the PDM.
  3. Turn ON the ignition, with the engine OFF.
  4. Operate the passenger door power window from the switch at the driver door.

Does the window operate properly?

Go to Step 12

Go to Step 11

11

Select the Display DTCs function for the DDM.

Does the scan tool display DTC U1161 with a current status?

Go to Step 17

Go to Step 16

12

    Important: Operate the power window from the switch at either rear door before using the switch at the driver door. The following procedure assumes the power window operates properly.

  1. Turn OFF the ignition.
  2. Connect the RDM.
  3. Turn ON the ignition, with the engine OFF.
  4. Operate the left rear door power window from the switch at the driver door.

Does the window operate properly?

Go to Testing for Electrical Intermittents in Wiring Systems

Go to Step 13

13

Select the Display DTCs function for the DDM.

Does the scan tool display DTC U1162 with a current status?

Go to Step 17

Go to Step 16

14

Test the power door serial data circuit for an open between the DDM and any other door module.

Did you find and correct the condition?

Go to Step 23

Go to Step 19

15

Test the power door serial data circuit of the module that is not communicating for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 23

Go to Step 17

16

Inspect for poor connections at the harness connector of the DDM. 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 23

Go to Step 20

17

Inspect for poor connections at the harness connector of the passenger door module that is not communicating. 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 23

Go to Step 21

18

Inspect for poor connections at the harness connector of the 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 23

Go to Step 22

19

Repair the open ground circuit between splice S207 and G201. Refer to Circuit Testing and Wiring Repairs in Wiring System.

Did you complete the repair?

Go to Step 23

--

20

Replace the DDM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 23

--

21

Replace the inoperative door module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 23

--

22

Replace the DDSA. Refer to Front Door Switch Replacement .

Did you complete the replacement?

Go to Step 23

--

23
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 3

System OK