GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The Driver Door Module (DDM) Diagnostic Check is an organized approach in order to identify problems associated with the door control system. This check is the starting point for all module complaints and directs you to the next logical step in diagnosing the complaint. The module is a very reliable component and is not likely the cause of the malfunction. Most system complaints are linked to faulty wiring and connectors, and occasionally to components. Understanding the computer system and using the tables correctly will reduce diagnostic time and prevent unnecessary parts replacement.

Diagnostic Aids

    • The following conditions may result in an intermittent operation of the module with no diagnostic trouble code (DTC) stored:
       - Any condition which results in the interruption of power to the module
       - Out of range battery or ignition voltage

Specification
Normal module operating voltage: 9.0-16.0 V

       - A loose or damaged ground(s)
       - An open or shorted serial data line
    • An intermittent failure in the electronic system may be very difficult to detect and to accurately diagnose. The module tests for different malfunctions under different vehicle conditions. For this reason, a thorough test drive is often needed in order to repeat a malfunction. If the system malfunction is not repeated during the test drive, a good description of the complaint may be very useful in locating an intermittent malfunction. Faulty electrical connections or wiring cause most intermittent problems. When an intermittent condition is suspected, inspect the suspected circuits for the following conditions:
       - Poor mating of connector halves or backed out terminals
       - Improperly formed or damaged terminals
       - Wire chafing
       - Poor wire to terminal connections
       - Dirty or corroded terminals
       - Damage to connector bodies
    • Use the J 35616 whenever a diagnostic procedure requests probing or checking a terminal. Using this adapter will ensure that no damage to the terminal will occur, and will give an idea of whether contact tension is sufficient.
    • If the DTC is a history DTC, the problem may be intermittent. Perform the tests shown while moving related wiring and connectors. This can often cause the malfunction to occur. Perform a thorough inspection of all related wiring and connectors pertaining to the history DTC stored.
    • Exit all scan tool tests before cycling the ignition OFF to ON unless the scan tool instructions direct otherwise. Follow the operating instructions in the scan tool operator's manual. Failure to follow these instruction may cause the following conditions:
      • DTCs set.
      • Vehicle system malfunctions
      • False DTCs set.
      • Scan tool malfunctions

Step

Action

Value(s)

Yes

No

1

  1. Turn OFF the ignition switch.
  2. Install a scan tool.
  3. Turn ON the ignition switch.
  4. Attempt to establish communication with the driver door module (DDM).

Does the scan tool communicate with the DDM?

--

Go to Step 3

Go to Step 2

2

Attempt to establish communications with the other modules connected to the same serial data line (PCM, EBTCM, IPC, etc.).

Does the scan tool communicate with the other modules?

--

Go to Scan Tool Does Not Communicate with Class 2 Data Line in Wiring Systems

Go to Diagnostic System Check - Data Link Communications in Wiring Systems

3

Select Display DDM DTC function with the scan tool.

Are any current DTCs stored?

--

Go to Step 4

Go to Step 5

4

Are U1016, U1064, U1065, U1066, U1255, U1300 and/or U1301 Loss of Class 2 Serial Data Communication DTCs set?

--

Go to Diagnostic Trouble Code (DTC) List/Type in Wiring Systems

Go to Diagnostic Trouble Code (DTC) List/Type

5

Is the customer complaint with the power mirrors?

--

Go to Outside Mirrors System Check

Go to Step 6

6

Is the customer complaint with the power door locks?

--

Go to Power Door Locks System Check

Go to Power Windows System Check