Possible Causes

DTCs set in other modules
Network communication concern
Steering wheel rotation sensor
SCCM (vehicles with active park assist)
PSCM (vehicles without active park assist)

Fig 1: Antilock Braking System (ABS) Module Connector - C135

Courtesy of FORD MOTOR COMPANY

Harness Side

LB1: CHECK FOR DTCS IN OTHER MODULES

Ignition ON, engine OFF.
Retrieve the continuous memory DTCs.
Record any ABS module DTCs.

Are there are DTCs present in the PSCM, RCM or SCCM?

Yes	No
DIAGNOSE all other module DTCs before diagnosing ABS module DTCs C0051:xx. For PSCM DTCs, REFER to POWER STEERING . For RCM DTCs, REFER to DTC CHART: RESTRAINT CONTROL MODULE (RCM) . For SCCM DTCs, REFER to STEERING WHEEL AND COLUMN ELECTRICAL COMPONENTS .	Go to LB2.

LB2: CHECK THE ABS MODULE DTCS

Review the ABS module DTCs recorded in the previous step.

Are any communication (U-Codes) or wheel speed sensor DTCs present in the ABS module?

Yes	No
DIAGNOSE all ABS module communication (U-Code) and wheel speed sensor DTCs before diagnosing any C0051:xx DTCs. Go to the ANTI-LOCK BRAKE SYSTEM (ABS) AND STABILITY CONTROL .	Go to LB3.

LB3: VERIFY STABILITY CONTROL SENSOR CALIBRATION

Using a diagnostic scan tool, carry out the IVD Initialization routine. Follow the diagnostic scan tool directions.
Ignition OFF.
Ignition ON, engine OFF.
Test drive the vehicle above 12 km/h (7 mph) and make at least one left turn and one right turn.
Carry out the ABS self-test.

Are there any C0051:xx DTCs present in the ABS module?

Yes	No
For vehicles equipped with active park assist, Go to LB4. For all others, Go to LB6.	The condition causing the concern is no longer present. The concern was most likely due to an incomplete calibration or a failed calibration of the stability control sensors.

LB4: CHECK THE SCCM STEERING WHEEL ANGLE PID

Start the engine.
Access the SCCM and monitor the SW_ANGLE (ANGL) PID.
Monitor the PID while slowly turning the steering wheel one complete revolution to the left and then to the right.

Does the PID display increase smoothly by 1.5 degrees and display a complete 360 degree rotation?

Yes	No
Go to LB6.	Go to LB5.

LB5: CENTER THE STEERING WHEEL ROTATION SENSOR

Ignition OFF.
Center the clockspring and steering wheel rotation sensor. Refer to the STEERING WHEEL ROTATION SENSOR
Test drive the vehicle at speeds greater than 20 km/h (12 mph) and make at least 1 left turn and 1 right turn.
Carry out the ABS self-test.

Are there any C0051:xx DTCs present in the ABS module?

Yes	No
INSTALL a new steering wheel rotation sensor. REFER to STEERING WHEEL ROTATION SENSOR .	The concern is not present or cannot be recreated at this time. The DTC may have been set due to an off center steering wheel rotation sensor.

LB6: CHECK THE ABS MODULE WHEEL SPEED SENSOR PIDS

Ignition ON, engine OFF.
Access the ABS and monitor the LF_WSPD (SPD) PID.
Access the ABS and monitor the LR_WSPD (SPD) PID.
Access the ABS and monitor the RF_WSPD (SPD) PID.
Access the ABS and monitor the RR_WSPD (SPD) PID.

Are the wheel speed PIDs within 5 km/h (3 mph) of each other and the vehicle speed as indicated on the speedometer?

Yes	No
Go to LB7.	INSTALL a new WSS. INSTALL a new wheel speed sensor for any sensor not matching the others or the speedometer. REFER to FRONT WHEEL SPEED SENSOR or REAR WHEEL SPEED SENSOR .

LB7: CHECK THE ABS MODULE YAW RATE VALUE PID

NOTE: The vehicle must be on level ground and at a complete standstill. Any vehicle movement results in false values for this test.

Access the ABS and monitor the YAW_RATE (ANGV) PID.

Is the PID value between -0.05 and 0.05?

Yes	No
Go to LB8.	Go to LB11.

LB8: CHECK THE ABS MODULE LATERAL ACCELERATION PID

NOTE: The vehicle must be on level ground and at a complete standstill. Any vehicle movement results in false values for this test.

Access the ABS and monitor the LAT_ACCL (ACC) PID.

Is the PID value between -0.4 and 0.4?

Yes	No
Go to LB9.	Go to LB11.

LB9: CHECK THE ABS MODULE LONGITUDINAL ACCELERATION SENSOR PID

NOTE: The vehicle must be on level ground and at a complete standstill. Any vehicle movement results in false values for this test.

Access the ABS and monitor the LONG_ACCL (ACC) PID.

Is the PID value between -0.4 and 0.4?

Yes	No
Go to LB10.	Go to LB11.

LB10: CHECK THE ABS MODULE ROLL RATE PID

NOTE: The vehicle must be on level ground and at a complete standstill. Any vehicle movement results in false values for this test.

Access the ABS and monitor the ROLL_RATE (ANGV) PID.

Is the PID value between -0.4 and 0.4?

Yes	No
For vehicles equipped with active park assist, Go to LB13. For all others, Go to LB15.	Go to LB11.

LB11: CHECK THE RCM INSTALLATION AND MOUNTING SURFACE

WARNING: Turn the ignition OFF and wait one minute to deplete the backup power supply. Failure to follow this instruction may result in serious personal injury or death in the event of an accidental deployment.

Ignition OFF.
Wait one minute.
RCM_A connector disconnected.
RCM_B connector disconnected.
Inspect the RCM installation and make sure the fasteners are fully seated and tightened to specifications. REFER to RESTRAINTS CONTROL MODULE (RCM) .
Inspect the RCM mounting surface for damage, corrosion or dirt.

Is the RCM installed correctly and is the mounting surface clean and free from damage?

Yes	No
Go to LB12.	CLEAN, REPAIR, REINSTALL or INSTALL new as necessary. REFER to RESTRAINTS CONTROL MODULE (RCM) .

LB12: CHECK FOR CORRECT RCM OPERATION

Inspect and repair all disconnected electrical connectors for the following:
- inspect the connectors (including any in-line connectors) for pushed-out, loose or spread terminals and loose or frayed wire connections at terminals.
- inspect the wire harness for any damage, pinched, cut or pierced wires.
- inspect RCM C310A and C310B CPA lever-lock for correct operation. Refer to RESTRAINTS CONTROL MODULE (RCM) .
- repair any concerns found. Refer to OEM CONNECTOR REPAIR PROCEDURES Connector Repair Procedures for schematic and connector information.
RCM_B connector connected. Make sure the connector seats and latches correctly.
RCM_A connector connected. Make sure the connector seats and latches correctly.
Test drive the vehicle at speeds greater than 20 km/h (12 mph) and make at least 1 left turn and 1 right turn.
Carry out the ABS self-test.

Are any C0051:xx DTCs present in the ABS module?

Yes	No
INSTALL a new RCM. CHECK OASIS for any applicable Technical Service Bulletins TSBs. If a TSB exists for this concern, DISCONTINUE this test and FOLLOW the TSB instructions. If no TSBs address this concern, INSTALL a new RCM. REFER to RESTRAINTS CONTROL MODULE (RCM) .	The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector, high network traffic or an intermittent fault condition. ADDRESS the root cause of any connector or pin issues.

LB13: CHECK FOR CORRECT STEERING WHEEL ROTATION SENSOR OPERATION

Ignition OFF.
ABS Module connector disconnected. (C135)
RCM_A connector disconnected. (if not previously disconnected)
RCM_B connector disconnected. (if not previously disconnected)
SCCM_A connector disconnected.
SCCM_B connector disconnected.
Disconnect all in-line electrical connectors between the ABS module, the SASM and the RCM.
Inspect and repair all disconnected electrical connectors for the following:
- corrosion (install new connector or terminal - clean module pins)
- damaged or bent pins - install new terminals or pins
- pushed-out pins - install new pins as necessary
- spread terminals - install new terminals as necessary
Remove the steering wheel rotation sensor. Refer to STEERING WHEEL ROTATION SENSOR .
- inspect the connectors for corrosion, loose or spread terminals and loose wire connections at terminals.
- inspect the wire harnesses for any damage, pinched, cut or pierced wires.
- repair any concerns found. Refer to OEM CONNECTOR REPAIR PROCEDURES Connector Repair Procedures for schematic and connector information.
Install the steering wheel rotation sensor. Refer to STEERING WHEEL ROTATION SENSOR .
Connect all in-line electrical connectors between the ABS module, the SASM and the RCM. Make sure the connectors seat and latch correctly.
SCCM_B connector connected. Make sure the connector seats and latches correctly.
SCCM_A connector connected. Make sure the connector seats and latches correctly.
RCM_B connector connected. Make sure the connector seats and latches correctly.
RCM_A connector connected. Make sure the connector seats and latches correctly.
ABS Module connector connected. (C135) Make sure the connector seats and latches correctly.
Test drive the vehicle at speeds greater than 20 km/h (12 mph) and make at least 1 left turn and 1 right turn.
Carry out the ABS self-test.

Are any C0051:xx DTCs present in the ABS module?

Yes	No
INSTALL a new steering wheel rotation sensor. REFER to STEERING WHEEL ROTATION SENSOR . Go to LB14.	The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector, high network traffic or an intermittent fault condition. ADDRESS the root cause of any connector or pin issues.

LB14: CHECK FOR ABS MODULE DTCS

Ignition ON, engine OFF.
Clear the ABS DTCs.
Test drive the vehicle at speeds greater than 20 km/h (12 mph) and make at least 1 left turn and 1 right turn.
Carry out the ABS self-test.

Are any C0051:xx DTCs present in the ABS module?

Yes	No
Go to LB15.	For all other ABS module DTCs, REFER to the ANTI-LOCK BRAKE SYSTEM (ABS) AND STABILITY CONTROL . If there are no DTCs in the ABS module, the repair is complete.

LB15: CHECK FOR CORRECT PSCM OPERATION

Ignition OFF.
ABS Module connector disconnected. (C135)
RCM_A connector disconnected. (if not previously disconnected)
RCM_B connector disconnected. (if not previously disconnected)
PSCM_A connector disconnected.
PSCM_B connector disconnected.
Disconnect all in-line electrical connectors between the ABS module, the PSCM and the RCM.
Inspect and repair all disconnected electrical connectors for the following:
- corrosion (install new connector or terminal - clean module pins)
- damaged or bent pins - install new terminals or pins
- pushed-out pins - install new pins as necessary
- spread terminals - install new terminals as necessary
Connect all in-line electrical connectors between the ABS module, the PSCM and the RCM. Make sure the connectors seat and latch correctly.
PSCM_B connector connected. Make sure the connector seats and latches correctly.
PSCM_A connector connected. Make sure the connector seats and latches correctly.
RCM_B connector connected. Make sure the connector seats and latches correctly.
RCM_A connector connected. Make sure the connector seats and latches correctly.
ABS Module connector connected. (C135) Make sure the connector seats and latches correctly.
Test drive the vehicle at speeds greater than 20 km/h (12 mph) and make at least 1 left turn and 1 right turn.
Carry out the ABS self-test.

Are any C0051:xx DTCs present in the ABS module?

Yes	No
INSTALL a new EPAS gear. CHECK OASIS for any applicable Technical Service Bulletins TSBs. If a TSB exists for this concern, DISCONTINUE this test and FOLLOW the TSB instructions. If no TSBs address this concern, INSTALL a new PSCM. REFER to POWER STEERING SYSTEM . ORDER a replacement PSCM and INCLUDE the RVC on the form. If this is a Ford paid repair, INCLUDE the RVC on the warranty claim form.	The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector, high network traffic or an intermittent fault condition. ADDRESS the root cause of any connector or pin issues.