The lock switch or switch circuit that failed and generated this diagnostic trouble code (DTC) is wired to either the driver door switch assembly (DDSA) or the front passenger door module (PDM). The driver door lock switch and the front passenger door lock switch differ slightly in the way they are wired and in which module processes their respective signal inputs, but they operate in much the same way.

The driver door lock switch is supplied voltage, via a lock signal circuit, and voltage, via a unlock signal circuit, by the driver door switch assembly (DDSA). The driver door lock switch ground circuit is supplied by the driver door module. Driver door lock switch signals are inputs to the DDSA.

The front passenger door lock switch is supplied voltage, via a lock signal circuit, and voltage, via a unlock signal circuit, by the front passenger door module (PDM). The front passenger door lock switch ground circuit is also supplied by the PDM. Front passenger door lock switch signals are inputs to the PDM.

When either lock switch is operated, the normally open contacts of the lock switch signal circuit are closed to ground. Voltage flows through the signal circuit, switch contacts, and ground circuit, to provide, either the DDSA, or the PDM with a signal input. Both the DDSA and the PDM send their switch signal input information to the driver door module (DDM) via the power door serial data circuit. When a door lock switch circuit is closed to ground for too long, the DDM is informed and sets the appropriate DTC.

On a normally functioning system with no failures present, the DDM, upon receiving a lock switch request from the DDSA or PDM, relays the request to the rear integration module (RIM), which is the master of all lock operations, as a Class 2 message. The RIM checks to see if conditions are correct for the function requested to be performed, and, if all conditions are correct, the RIM sends its OK back to the DDM. The DDM then locks or unlocks the driver door, and sends a power door serial data message to all other door modules to lock or unlock their respective doors.

If the DDM receives the message that, either a passenger door lock switch circuit is closed for more than 30 continuous seconds, or a driver door lock switch circuit is closed for more than 255 seconds (4.25 minutes), the DDM sets the DTC.

The DDM ignores any message for the lock switch designated by the DTC and prevents lock movement from the affected switch. The DDM will respond to other lock switch messages.

The DDM clears this current DTC when the failed switch message is no longer received and stores a history DTC. The history DTC will clear either after 50 OFF/ON ignition switch cycles without a repeated failure or in response to a scan tool command.

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

2. This step checks the module input state using the normal input status.

3. This step Verifys that the input is seen by the module.

4. This step verifys that the signal circuits to the module are open with the switch removed.

5. This step verifys that the signal circuits are not shorted.