Operation CHARM: Car repair manuals for everyone.

Pinpoint Test G: The Door Lock Switches Operate Only One Way




Handles, Locks, Latches and Entry Systems

Pinpoint Test G: The Door Lock Switches Operate Only One Way - MKZ

Refer to Wiring Diagram Set 110, Power Door Locks for schematic and connector information. [1][2]Diagrams By Number

Normal Operation

The Smart Junction Box (SJB) sends voltage signals to the passenger door lock control switch through the lock and unlock input circuits. When the lock or unlock switch is pressed, the corresponding voltage signal is routed to ground, signalling the SJB (Smart Junction Box) to lock or unlock the passenger doors and send a lock or unlock command to the Driver Door Module (DDM) over the Medium Speed Controller Area Network (MS-CAN).

The DDM (Driver Door Module) sends voltage signals to the driver door lock control switch through the lock and unlock input circuits. When the lock or unlock switch is pressed, the corresponding voltage signal is routed to ground, signalling the DDM (Driver Door Module) to lock or unlock the driver door and send a lock or unlock command to the SJB (Smart Junction Box) over the MS-CAN (Medium Speed Controller Area Network).

The door lock control switches have a dedicated ground circuit.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors

- Door lock control switch

- DDM (Driver Door Module)

- SJB (Smart Junction Box)

PINPOINT TEST G : THE DOOR LOCK SWITCHES OPERATE ONLY ONE WAY - MKZ

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

G1 RETRIEVE THE RECORDED DDM (Driver Door Module) AND SJB (Smart Junction Box) DTCs FROM BOTH THE SELF-TESTS

- Check for recorded DDM (Driver Door Module) and SJB (Smart Junction Box) DTCs from the self-tests.

Are any DTCs recorded?

Yes
For DDM (Driver Door Module) DTC B2574 or B2575 and SJB (Smart Junction Box) DTC B2A25, GO to Pinpoint Test H. Pinpoint Test H: DTC B2A25, B2574, Or B2575

For all other DTCs, REFER to DTC Charts. Doors, Hood and Trunk

No
GO to G2.

G2 CHECK THE SUSPECT DOOR LOCK CONTROL SWITCH FOR CORRECT OPERATION

- Disconnect: Inoperative Door Lock Control Switch.

- Carry out the door lock control switch component test.


Is the door lock control switch OK?

Yes
If the driver door lock control switch was the switch tested, GO to G3.

If the passenger door lock control switch was the switch tested, GO to G4.

No
INSTALL a new door lock control switch. REFER to Door Lock Control Switch . TEST the system for normal operation.

G3 CHECK THE DRIVER LOCK AND UNLOCK INPUT CIRCUITS FOR AN OPEN AT THE DDM (Driver Door Module)

- Ignition OFF.

- Disconnect: DDM (Driver Door Module) C568A.

- If the doors do not lock, measure the resistance between the DDM (Driver Door Module) C568A-5, circuit CPL42 (GY/YE), harness side and the LH door lock control switch C505-1, circuit CPL42 (GY/YE), harness side.





- If the doors do not unlock, measure the resistance between the DDM (Driver Door Module) C568A-6, circuit CPL43 (VT/GY), harness side and the LH door lock control switch C505-3, circuit CPL43 (VT/GY), harness side.





Are the resistances less than 5 ohms?

Yes
GO to G5.

No
REPAIR the circuit in question for an open. TEST the system for normal operation.

G4 CHECK THE PASSENGER LOCK AND UNLOCK INPUT CIRCUITS FOR AN OPEN AT THE SJB (Smart Junction Box)

- Ignition OFF.

- Disconnect: SJB (Smart Junction Box) C2280C.

- If the doors do not lock, measure the resistance between the SJB (Smart Junction Box) C2280C-17, circuit CPK19 (BU/GN), harness side and the RH door lock control switch C605-1, circuit CPK19 (BU/GN), harness side.





- If the doors do not unlock, measure the resistance between the SJB (Smart Junction Box) C2280C-4, circuit CPK23 (YE/VT), harness side and the RH door lock control switch C605-3, circuit CPK23 (YE/VT), harness side.





Are the resistances less than 5 ohms?

Yes
GO to G6.

No
REPAIR the circuit in question. TEST the system for normal operation.

G5 CHECK FOR CORRECT DDM (Driver Door Module) OPERATION

- Disconnect all the DDM (Driver Door Module) connectors.

- Check for:
- corrosion

- damaged pins

- pushed-out pins


- Connect all the DDM (Driver Door Module) connectors and make sure they seat correctly.

- Operate the system and verify the concern is still present.

Is the concern still present?

Yes
INSTALL a new DDM (Driver Door Module). REFER to Driver Door Module (DDM) . TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.

G6 CHECK FOR CORRECT SJB (Smart Junction Box) OPERATION

- Disconnect all the SJB (Smart Junction Box) connectors.

- Check for:
- corrosion

- damaged pins

- pushed-out pins


- Connect all the SJB (Smart Junction Box) connectors and make sure they seat correctly.

- Operate the system and verify the concern is still present.

Is the concern still present?

Yes
INSTALL a new SJB (Smart Junction Box). TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.