Pinpoint Test H: DTC B2A25, B2574, Or B2575
Handles, Locks, Latches and Entry Systems
Pinpoint Test H: DTC B2A25, B2574, Or B2575
Refer to Wiring Diagram Set 110, Power Door Locks for schematic and connector information. [1][2]Diagrams By Number
Normal Operation - MKZ
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.
Fusion
The SJB (Smart Junction Box) sends voltage signals to both door lock control switches 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 doors. The door lock control switches have a dedicated ground circuit.
- DTC B2574 (Drivers Door LOCK Switch Short to Ground)- a continuous and on-demand DTC that sets when the DDM (Driver Door Module) detects a short to ground on the lock input circuit. This code will also set if the driver door lock control switch is pressed for longer than 2 minutes.
- DTC B2575 (Drivers Door UNLOCK Switch Short to Ground)- a continuous and on-demand DTC that sets when the DDM (Driver Door Module) detects a short to ground on the unlock circuit. This code will also set if the driver door lock control switch is pressed for longer than 2 minutes.
- DTC B2A25 (Trim Panel Lock Switch Circuit Failure)- an on-demand DTC that sets when the SJB detects a short to ground from the lock or unlock request input circuits. This DTC may also set if either of the door lock control switches are pressed for longer than 2 minutes.
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 H : DTC B2A25, B2574, OR B2575
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
H1 CHECK THE RECORDED SJB (Smart Junction Box) DTCs FROM THE SELF-TEST
- Check the recorded results from the SJB (Smart Junction Box) self-test.
Is DTC B2A25 present?
Yes
GO to H2.
No
For DTCs B2574 or B2575, GO to H5.
H2 CHECK THE RH DOOR LOCK CONTROL SWITCH
- Disconnect: RH Door Lock Control Switch C605.
- Repeat the SJB (Smart Junction Box) self-test.
Is DTC B2A25 retrieved again?
Yes
For Fusion and Milan, LEAVE the switch disconnected. GO to H3.
For MKZ, LEAVE the switch disconnected. GO to H4.
No
INSTALL a new RH door lock control switch. REFER to Door Lock Control Switch . TEST the system for normal operation.
H3 CHECK THE LH DOOR LOCK CONTROL SWITCH - FUSION
- Disconnect: LH Door Lock Control Switch C505.
- Repeat the SJB (Smart Junction Box) self-test.
Is DTC B2A25 retrieved again?
Yes
LEAVE the switch disconnected. GO to H4.
No
INSTALL a new LH door lock control switch. REFER to Door Lock Control Switch . TEST the system for normal operation.
H4 CHECK THE SJB (Smart Junction Box) LOCK INPUT CIRCUIT OR THE UNLOCK INPUT CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: SJB (Smart Junction Box) C2280C.
- Measure the resistance between the RH door lock control switch C605-1, circuit CPK19 (BU/GN), harness side and ground; and between the RH door lock control switch C605-3, circuit CPK23 (YE/VT), harness side and ground.
Are the resistances greater than 10,000 ohms?
Yes
GO to H8.
No
REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test.
H5 CHECK THE LH DOOR LOCK CONTROL SWITCH - MKZ
- Disconnect: LH Door Lock Control Switch C505.
- Repeat the DDM (Driver Door Module) self-test.
Is DTC B2574 or B2575 retrieved?
Yes
LEAVE the switch disconnected. GO to H6.
No
INSTALL a new LH door lock control switch. REFER to Door Lock Control Switch . TEST the system for normal operation.
H6 CHECK THE DDM (Driver Door Module) LOCK INPUT CIRCUIT OR THE UNLOCK INPUT CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: DDM (Driver Door Module) C568A.
- Measure the resistance between the LH door lock control switch C505-1, circuit CPL42 (GY/YE), harness side and ground; and between the LH door lock control switch C505-3, circuit CPL43 (VT/GY), harness side and ground.
Are the resistances greater than 10,000 ohms?
Yes
GO to H7.
No
REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test.
H7 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.
H8 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.