Visual Inspection and Diagnostic Pre-checks

Make sure the wheel speed sensor harness is routed correctly and is undamaged.

Make sure the wheel speed sensor electrical connector is free from any corrosion or other contaminants.

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

Courtesy of FORD MOTOR COMPANY

CONNECTOR PIN REFERENCE (HARNESS SIDE)

Circuit	Pin
LR WSS LO (Left Rear Wheel Speed Sensor Low) - RCA18	6 (BROWN/GREEN)
LR WSS HI (Left Rear Wheel Speed Sensor High) - VCA04	7 (BLUE/ORANGE)
RR WSS LO (Right Rear Wheel Speed Sensor Low) - RCA20	10 (BROWN)
RR WSS HI (Right Rear Wheel Speed Sensor High) - VCA06	11 (WHITE/ORANGE)

Fig 2: Left Rear Wheel Speed Sensor Connector - C440

Courtesy of FORD MOTOR CO.

CONNECTOR PIN REFERENCE (HARNESS SIDE)

Circuit	Pin
LR WSS LO (Left Rear Wheel Speed Sensor Low) - RCA18	2 (BROWN/GREEN)
LR WSS HI (Left Rear Wheel Speed Sensor High) - VCA04	1 (BLUE/ORANGE)

Fig 3: Right Rear Wheel Speed Sensor Connector - C426

Courtesy of FORD MOTOR CO.

CONNECTOR PIN REFERENCE (HARNESS SIDE)

Circuit	Pin
RR WSS LO (Right Rear Wheel Speed Sensor Low) - RCA20	2 (BROWN)
RR WSS HI (Right Rear Wheel Speed Sensor High) - VCA06	1 (WHITE/ORANGE)

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

N1: CHECK FOR FAULT REPEATABILITY

Ignition ON, engine OFF.
Clear the ABS DTCs.
Ignition OFF.
Ignition ON, engine OFF.
Test drive the vehicle above 20 km/h (12 mph).
Carry out the ABS self-test.

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

Yes	No
For failure type byte 01 (General Electrical Failure), 12 (Circuit Short to Ground) or 15 (Circuit Short to Battery or Open Circuit), Go to N2. For failure type byte 11 (Circuit Short to Ground) or 14 (Circuit Short to Ground or Open Circuit), Go to N3.	The system is operating correctly at this time. INSPECT both front wheel speed sensor electrical connectors and the ABS module electrical connector. REPAIR or CLEAN the connector as necessary. ADDRESS the root cause of any connector or pin issues.

N2: CHECK THE WHEEL SPEED SENSOR CIRCUITS FOR A SHORT TO BATTERY VOLTAGE

Ignition OFF.
ABS Module connector disconnected. (C135)
Disconnect the suspect wheel speed sensor.
Ignition ON, engine OFF.
For the left rear wheel speed sensor:

Measure the voltage between:

(+) Left Rear Wheel Speed Sensor (C440) Connector, Harness Side	(-)
LR WSS LO - RCA18 (BROWN/GREEN) - Pin 2	Ground
LR WSS HI - VCA04 (BLUE/ORANGE) - Pin 1	Ground

For the right rear wheel speed sensor:

Measure the voltage between:

(+) Right Rear Wheel Speed Sensor (C426) Connector, Harness Side	(-)
RR WSS LO - RCA20 (BROWN) - Pin 2	Ground
RR WSS HI - VCA06 (WHITE/ORANGE) - Pin 1	Ground

Is any voltage present?

Yes	No
REPAIR the circuit.	Go to N3.

N3: CHECK THE WHEEL SPEED SENSOR CIRCUITS FOR A SHORT TO GROUND

Ignition OFF.
ABS Module connector disconnected. (C135) (if not previously disconnected)
Disconnect the suspect wheel speed sensor (if not previously disconnected).
For the left rear wheel speed sensor:

Measure the resistance between:

(+) ABS Module (C135) Connector, Harness Side	(-)
LR WSS LO - RCA18 (BROWN/GREEN) - Pin 6	Ground
LR WSS HI - VCA04 (BLUE/ORANGE) - Pin 7	Ground

For the right rear wheel speed sensor:

Measure the resistance between:

(+) ABS Module (C135) Connector, Harness Side	(-)
RR WSS LO - RCA20 (BROWN) - Pin 10	Ground
RR WSS HI - VCA06 (WHITE/ORANGE) - Pin 11	Ground

Are the resistances greater than 10, 000 ohms?

Yes	No
Go to N4.	REPAIR the circuit.

N4: CHECK FOR SHORTED WHEEL SPEED SENSOR CIRCUITS

For the left rear wheel speed sensor:

Measure the resistance between:

(+) Left Rear Wheel Speed Sensor (C440) Connector, Harness Side	(-) Left Rear Wheel Speed Sensor (C440) Connector, Harness Side
LR WSS HI - VCA04 (BLUE/ORANGE) - Pin 1	LR WSS LO - RCA18 - Pin 2

For the right rear wheel speed sensor:

Measure the resistance between:

(+) Right Rear Wheel Speed Sensor (C426) Connector, Harness Side	(-) Right Rear Wheel Speed Sensor (C426) Connector, Harness Side
RR WSS HI - VCA06 (WHITE/ORANGE) - Pin 1	RR WSS LO - RCA20 - Pin 2

Is the resistance greater 10, 000 ohms?

Yes	No
Go to N5.	REPAIR the circuit.

N5: CHECK THE WHEEL SPEED CIRCUITS FOR AN OPEN

For the left rear wheel speed sensor:

Measure the resistance between:

(+) ABS Module (C135) Connector, Harness Side	(-) Left Rear Wheel Speed Sensor (C440) Connector, Harness Side
LR WSS LO - RCA18 (BROWN/GREEN) - Pin 6	LR WSS LO - RCA18 - Pin 2
LR WSS HI - VCA04 (BLUE/ORANGE) - Pin 7	LR WSS HI - VCA04 - Pin 1

For the right rear wheel speed sensor:

Measure the resistance between:

(+) ABS Module (C135) Connector, Harness Side	(-) Right Rear Wheel Speed Sensor (C426) Connector, Harness Side
RR WSS LO - RCA20 (BROWN) - Pin 10	RR WSS LO - RCA20 - Pin 2
RR WSS HI - VCA06 (WHITE/ORANGE) - Pin 11	RR WSS HI - VCA06 - Pin 1

Are the resistances less than 3 ohms?

Yes	No
Go to N6.	REPAIR the circuit.

N6: CHECK THE ABS MODULE OUTPUT

NOTE: Make sure all test connections are made at the wheel speed sensor before the ignition is set to ON.

NOTE: Use a meter with a min-max feature or recording capabilities to obtain accurate measurements. The ABS module disables the voltage output immediately if the wheel speed sensor is not present.

ABS Module connector connected. (C135)
Connect the meter to the suspect wheel speed sensor electrical connector, harness side.
Set the meter to measure DC voltage.
Set the meter range to greater than 15 volts.
Enable the min-max or recording feature on the meter.
Ignition ON, engine OFF.
For the left rear wheel speed sensor:

Measure the voltage between:

(+) Left Rear Wheel Speed Sensor (C440) Connector, Harness Side	(-) Left Rear Wheel Speed Sensor (C440) Connector, Harness Side
LR WSS HI - VCA04 (BLUE/ORANGE) - Pin 1	LR WSS LO - RCA18 - Pin 2

For the right rear wheel speed sensor:

Measure the voltage between:

(+) Right Rear Wheel Speed Sensor (C426) Connector, Harness Side	(-) Right Rear Wheel Speed Sensor (C426) Connector, Harness Side
RR WSS HI - VCA06 (WHITE/ORANGE) - Pin 1	RR WSS LO - RCA20 - Pin 2

Check the maximum recorded voltage on the meter.

Is the voltage greater 10 volts?

Yes	No
INSTALL a new WSS. REFER to Anti-Lock Brake System (ABS) And Stability Control (Hybrid/Energi) .	Go to N7.

N7: VERIFY ALL WIRING CONNECTIONS

Ignition OFF.
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 N8.	REPAIR the affected connectors or terminals. Refer to OEM Connector Repair Procedures (Hybrid/Energi) .

N8: CHECK FOR CORRECT ABS MODULE OPERATION

ABS Module connector connected. (C135) Make sure the connector seats and latches correctly.
Connect the suspect wheel speed sensor electrical connector. Make sure the connector seats and latches correctly.
Operate the system and determine if the concern is still present.

Is the concern still present?

Yes

No

INSTALL a new ABS module.
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 ABS module. REFER to Anti-Lock Brake System (ABS) And Stability Control (Hybrid/Energi) .
ORDER a replacement ABS module and INCLUDE the RVC on the form.
If this is a Ford paid repair, INCLUDE the RVC on the warranty claim form.
When complete, SELECT the "X" in the top right corner to CLOSE this procedure and RETURN to the PTS web site.

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.