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 (Fusion/Milan/MKZ, Fusion Hybrid, Milan Hybrid, MKZ Hybrid), Power Door Locks for schematic and connector information. 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 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 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 to lock or unlock the driver door and send a lock or unlock command to the SJB over the MS-CAN.
The door lock control switches have a dedicated ground circuit.
Fusion/Milan
The SJB 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 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 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 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
- SJB
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.
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H1 CHECK THE RECORDED SJB DTCs FROM THE SELF-TEST
- Check the recorded results from the SJB self-test.
- Is DTC B2A25 present?
Yes
GO to H2.
No
For DTCs B2574 or B2575, GO to H5.
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H2 CHECK THE RH DOOR LOCK CONTROL SWITCH
- Disconnect: RH Door Lock Control Switch C605 .
- Repeat the SJB 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 Service and Repair. TEST the system for normal operation.
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H3 CHECK THE LH DOOR LOCK CONTROL SWITCH - FUSION/MILAN
- Disconnect: LH Door Lock Control Switch C505 .
- Repeat the SJB 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 Service and Repair. TEST the system for normal operation.
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H4 CHECK THE SJB LOCK INPUT CIRCUIT OR THE UNLOCK INPUT CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: SJB 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.
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H5 CHECK THE LH DOOR LOCK CONTROL SWITCH - MKZ
- Disconnect: LH Door Lock Control Switch C505 .
- Repeat the DDM 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 Service and Repair. TEST the system for normal operation.
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H6 CHECK THE DDM LOCK INPUT CIRCUIT OR THE UNLOCK INPUT CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: DDM 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.
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H7 CHECK FOR CORRECT DDM OPERATION
- Disconnect all the DDM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the DDM 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. REFER to Driver Door Module (DDM) Service and Repair. 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.
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H8 CHECK FOR CORRECT SJB OPERATION
- Disconnect all the SJB connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the SJB 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. REFER to Multifunction Electronic Modules Service and Repair. 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.
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