Pinpoint Test B : DTC P185D:00, P187C:00 And P187D:00

WARNING: This page is about a different car, the 2020 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Make sure the battery is fully charged before carrying out this pinpoint test.

B1 CHECK FOR TCCM DTCS
- Ignition ON.
- Set the ELDMSS to OFF.
- Enter the following diagnostic mode: TCCM Self-Test.
Are any DTCs present?

Yes GO to B2, For all other DTCs, REFER to the DTC Chart: TCCM .

No VERIFY the customer concern and GOSymptom Chart(s)

B2 CHECK FOR TCCM DTCS WITH THE ELD FIELD COIL DISCONNECTED

Ignition OFF.

Disconnect ELD Field Coil C4359.

Ignition ON.

Set the ELDMSS to OFF.

Enter the following diagnostic mode: TCCM Self-Test.

CLEAR the DTCs. REPEAT the self-test. Does DTC P185D:00, P187C:00 or P187D:00 return?

Yes

GO to B3

No	INSTALL a new ELD field coil. REFER to: Differential Carrier - Vehicles With: Electronic Locking Differential (ELD) . CLEAR the DTCs.

B3 CHECK THE ABS MODULE WHEEL SPEED SENSOR PIDS
- Enter the following diagnostic mode: ABS Module Datalogger.
- While driving the vehicle at 30 km/h (18 mph), monitor the following wheel speed sensor PIDs:
  - Left Front Wheel Speed Sensor (LF_WSPD)
  - Left Rear Wheel Speed Sensor (LR_WSPD)
  - Right Front Wheel Speed Sensor (RF_WSPD)
  - Right Rear Wheel Speed Sensor (RR_WSPD)
- Compare the speedometer reading to the wheel speed sensor PIDs.
Do the wheel speed sensor PIDs and speedometer speeds match within 1.5 km/h (1 mph)?

Yes GO to B4

No VERIFY that the 4 road wheels are the same size and have similar tread depth. CHECK the ABS for faults.

B4 CHECK RESISTANCE OF THE ELD FIELD COIL

Ignition OFF.

Disconnect ELD Field Coil C4359.

Measure:

Positive Lead	Measurement / Action	Negative Lead
ELD field coil pin 1 component side	Courtesy of FORD MOTOR COMPANY	ELD field coil pin 2 component side

Is the resistance between 2-4 ohms?

Yes

GO to B5

No	INSTALL a new ELD field coil. REFER to: Differential Carrier - Vehicles With: Electronic Locking Differential (ELD) .

B5 CHECK THE ELD FIELD COIL GROUND

Measure:

Positive Lead	Measurement / Action	Negative Lead
C4359-2	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance less than 3 ohms?

Yes

GO to B6

No	REPAIR the circuit.

B6 CHECK THE ELD DIFFERENTIAL LOCK CONTROL CIRCUIT FOR A SHORT TO GROUND

Ignition OFF.

Disconnect TCCM C2371B.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C2371B-9	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance greater than 10, 000 ohms?

Yes

GO to B7

No	REPAIR the circuit.

B7 CHECK THE ELD DIFFERENTIAL LOCK CONTROL CIRCUIT FOR AN OPEN

Ignition OFF.

Disconnect TCCM C2371A.

Disconnect ELD Field Coil C4359.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C2371B-9	Courtesy of FORD MOTOR COMPANY	C4359-1

Is the resistance less than 3 ohms?

Yes

GO to B8

No	REPAIR the circuit.

B8 CHECK FIELD COIL GROUND CIRCUIT

Measure:

Positive Lead	Measurement / Action	Negative Lead
C4359-2	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance less than 3 ohms?

Yes

GO to B9

No	REPAIR the circuit.

B9 CHECK FOR CORRECT TCCM OPERATION

Ignition OFF.

Disconnect and inspect all TCCM connectors.

Check for the following:
- corrosion (install new connector or terminals - clean module pins)
- damaged or bent pins - install new terminals/pins
- pushed-out pins - install new pins as necessary

Connect all TCCM connectors. Make sure they seat and latch correctly.

Operate the system and verify the concern is still present.

Is the concern still present?

Yes	INSTALL a new TCCM. REFER to: Transfer Case Control Module (TCCM) .

No	The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector. ADDRESS the root cause of the connector or pin issues.