Possible Causes

Wheels or tires
Wiring, terminals or connectors
RCM
ABS module

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

Fig 1: Antilock Braking System Module Connector (C135)

Courtesy of FORD MOTOR COMPANY

CIRCUIT AND PIN DESCRIPTION

Circuit	Pin
HS-CAN2- (High-Speed Controller Area Network 2 Low) - VDB26	43 (GRAY/BLUE)
HS-CAN2+ (High-Speed Controller Area Network 2 High) - VDB25	42 (GREEN/ORANGE)

Fig 2: Restraint Control Module-B Connector (C310B)

Courtesy of FORD MOTOR CO.

CIRCUIT AND PIN DESCRIPTION

Circuit	Pin
HS-CAN2- (High-Speed Controller Area Network 2 Low) - VDB26	47 (GRAY/BLUE)
HS-CAN2+ (High-Speed Controller Area Network 2 High) - VDB25	48 (GREEN/ORANGE)

Fig 3: Restraint Control Module-A Connector (C310A)

Courtesy of FORD MOTOR CO.

Harness Side

Circuit

G1: CHECK THE WHEELS AND TIRES

Inspect the wheels and tires for any damage or excessive wear.
Verify all wheels and tires are the same size and match the size indicated on the VC label.
Verify the inflation pressure of all 4 tires is correct as indicated on the VC label.

Are the wheels and tires OK?

Yes	No
Go to G2.	INSTALL the correct size wheel or tire or ADJUST tire pressure as necessary.

G2: CHECK THE COMMUNICATION NETWORK

Ignition ON, engine OFF.
Press the Read Vehicle Information button to view the results of the modules communicating on the network
Retrieve the continuous memory DTCs.

Does the RCM pass the Network Test?

Yes	No
Go to G3.	Refer to Module Communications Network article to diagnose the RCM does not communicate with the scan tool.

G3: RETRIEVE ALL DTCS FROM THE RCM

Carry out the RCM self-test.

Are any DTCs present?

Yes	No
DIAGNOSE the RCM DTCs first. REFER to Supplemental Restraint System article	Go to G4.

G4: CHECK THE ABS MODULE DTCS

Ignition ON, engine OFF.
Carry out the ABS self-test.

Is DTC U0151:xx or U0452:xx present?

Yes	No
Go to PINPOINT TEST BH .	Go to G5.

G5: VERIFY STABILITY CONTROL SENSOR CALIBRATION

Ignition OFF.
Ignition ON, engine OFF.
Test drive the vehicle above 12 km/h (7 mph) and at least once make a left turn and a right turn.
Carry out the ABS self-test.

Is one or more DTC shown in the ABS Module DTC Fault Trigger Conditions table present?

Yes	No
Go to G6.	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.

G6: CHECK THE ABS MODULE STABILITY CONTROL SENSOR PID VALUES

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

Ignition OFF.
Ignition ON, engine OFF.
Access the ABS and monitor the YAW_RATE (ANGV) PID.
Access the ABS and monitor the ROLL_RATE (ANGV) PID.
Access the ABS and monitor the LAT_ACCL (ACC) PID.
Access the ABS and monitor the LONG_ACCL (ACC) PID.

Are the YAW_RATE and ROLL_RATE PID values between -0.05 and 0.05, and are the LAT_ACCL and LONG_ACCL PID values between -0.04 and 0.04?

Yes	No
Go to G11.	Go to G7.

G7: CHECK THE PRIVATE HS-CAN CIRCUITS FOR A SHORT TO VOLTAGE

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. (C310A)
RCM_B connector disconnected. (C310B)
ABS Module connector disconnected. (C135)
Ignition ON, engine OFF.

Measure the voltage between:

(+) ABS Module (C135) Connector, Harness Side	(-)
HS-CAN2- - VDB26 (GRAY/BLUE) - Pin 43	Ground
HS-CAN2+ - VDB25 (GREEN/ORANGE) - Pin 42	Ground

Is any voltage present?

Yes	No
REPAIR the circuit.	Go to G8.

G8: CHECK THE PRIVATE HS-CAN CIRCUITS FOR A SHORT TO GROUND

Ignition OFF.

Measure the resistance between:

(+) ABS Module (C135) Connector, Harness Side	(-)
HS-CAN2- - VDB26 (GRAY/BLUE) - Pin 43	Ground
HS-CAN2+ - VDB25 (GREEN/ORANGE) - Pin 42	Ground

Are the resistances greater than 10, 000 ohms?

Yes	No
Go to G9.	REPAIR the circuit in question.

G9: CHECK THE PRIVATE HS-CAN CIRCUITS FOR A SHORT TOGETHER

Measure the resistance between:

(+) ABS Module (C135) Connector, Harness Side	(-) ABS Module (C135) Connector, Harness Side
HS-CAN2- - VDB26 (GRAY/BLUE) - Pin 43	HS-CAN2+ - VDB25 - Pin 42

Is the resistance greater than 10, 000 ohms?

Yes	No
Go to G10.	REPAIR the circuits.

G10: CHECK THE PRIVATE HS-CAN CIRCUITS FOR AN OPEN

Measure the resistance between:

(+) ABS Module (C135) Connector, Harness Side	(-) RCM_B (C310B) Connector, Harness Side
HS-CAN2- - VDB26 (GRAY/BLUE) - Pin 43	HS-CAN2- - VDB26 - Pin 47
HS-CAN2+ - VDB25 (GREEN/ORANGE) - Pin 42	HS-CAN2+ - VDB25 - Pin 48

Are the resistances less than 3 ohms?

Yes	No
Go to G11.	REPAIR the circuit in question.

G11: CHECK THE RCM INSTALLATION AND MOUNTING SURFACE

Ignition OFF.
Wait one minute.
RCM_A connector disconnected. (C310A) (if not previously disconnected)
RCM_B connector disconnected. (C310B) (if not previously disconnected)
Inspect the RCM installation, make sure the fasteners are fully seated and tightened to specifications. Refer to Supplemental Restraint System article
Inspect the RCM mounting surface for damage, corrosion or dirt.

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

Yes	No
Go to G12.	CLEAN or REPAIR the mounting surface or INSTALL a new RCM as necessary. REFER to Supplemental Restraint System article

G12: VERIFY ALL WIRING CONNECTIONS

Ignition OFF.
Wait one minute.
RCM_A connector disconnected. (C310A)
RCM_B connector disconnected. (C310B)
ABS Module connector disconnected. (C135)
Using a good light source, inspect all disconnected electrical connectors for the following:
- corrosion - install new connector or terminal and clean the 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

Are the connectors free of corrosion, damaged pins, bent pins, pushed-out pins and spread terminals?

Yes	No
Go to G13.	REPAIR the affected connectors or terminals. REFER to Connector Repair Procedures article for schematic and connector information.

G13: CHECK THE RCM FOR CORRECT OPERATION

ABS Module connector connected. (C135)
RCM_A connector connected. (C310A)
RCM_B connector connected. (C310B)
Operate the system and determine if the concern is still present.

Is the concern still present?

Yes	No
INSTALL a new RCM. CHECK OASIS for any service articles: TSB, GSB, SSM or FSA. If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions. If no services articles address this concern, INSTALL a new RCM. REFER to Supplemental Restraint System article ORDER a replacement RCM 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. ADDRESS the root cause of any connector or pin issues.

Yes

INSTALL a new RCM.
CHECK OASIS for any service articles: TSB, GSB, SSM or FSA.
If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions.
If no services articles address this concern, INSTALL a new RCM. REFER to Supplemental Restraint System article
ORDER a replacement RCM 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. ADDRESS the root cause of any connector or pin issues.