PINPOINT TEST AK : Wheel Speed Sensor Electrical Faults - Rear

AK1 CHECK FOR FAULT REPEATABILITY

Ignition ON.

Using a diagnostic scan tool, clear all ABS module DTCs.

Test drive the vehicle above 20 km/h (12.4 mph) and attempt to carry out at least 1 ABS stop.

Bring the vehicle to a safe stop.

Ignition OFF.

Ignition ON.

Using a diagnostic scan tool, carry out the ABS module self-test.

Is the DTC still present?

Yes	If the vehicle is not equipped with active park assist and the Rotunda Active Wheel Speed Sensor Tester is available , GO to AK2 . If the vehicle is equipped with active park assist or the Rotunda Active Wheel Speed Sensor Tester is not available , GO to AK4.
No	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.

AK2 CHECK THE ABS MODULE OUTPUT USING THE ROTUNDA ABS ACTIVE WHEEL SPEED SENSOR TESTER
- Ignition OFF.
- Disconnect suspect wheel speed sensor electrical connector.
- Connect the Rotunda ABS Active Wheel Speed Sensor Tester to the wheel speed sensor connectors.
- Ignition ON.
- Select the correct system polarity on the Rotunda ABS Active Wheel Speed Sensor Tester and turn the power switch to the ON position.
Is the tester output LED illuminated?

Yes GO to AK3.

No GO to AK5.

AK3 CHECK THE WHEEL SPEED SENSOR OUTPUT WITH THE ROTUNDA ABS ACTIVE WHEEL SPEED SENSOR TESTER

Raise the suspect wheel until it can spin freely. REFER to Jacking and Lifting , Lifting Points.

While monitoring the Rotunda ABS Active Wheel Speed Sensor Tester, slowly spin the suspect wheel.

Do the sensor output LEDs illuminate and flash and is the current overload LED not illuminated?

Yes	The system is operating correctly at this time. INSPECT all wheel speed sensor electrical connectors and the ABS module electrical connectors. REPAIR or CLEAN the connector as necessary. ADDRESS the root cause of any connector or pin issues.
No	INSTALL a new wheel speed sensor. REFER to Wheel Speed Sensor - Rear . CARRY OUT the following steps to clear the ABS module DTCs : DRIVE the vehicle at a speed greater than 20 km/h (12.4 mph), CYCLE the ignition from ON to OFF and back to ON, CLEAR the ABS module DTCs and CARRY OUT the ABS module self-test.

AK4 CHECK THE WHEEL SPEED SENSOR CIRCUITS FOR A SHORT TO BATTERY VOLTAGE

Ignition OFF.

Disconnect ABS module C135 .

Disconnect wheel speed sensor C440 .

Disconnect wheel speed sensor C426 .

Ignition ON.

For the LR wheel speed sensor, measure:

Positive Lead	Measurement / Action	Negative Lead
C135-36	Courtesy of FORD MOTOR COMPANY	Ground
C135-37	Courtesy of FORD MOTOR COMPANY	Ground

For the RR wheel speed sensor, measure:

Positive Lead	Measurement / Action	Negative Lead
C135-42	Courtesy of FORD MOTOR COMPANY	Ground
C135-43	Courtesy of FORD MOTOR COMPANY	Ground

Is any voltage present?

Yes	REPAIR the circuit.
No	For vehicles not equipped with active park assist, GO to AK5. For vehicles equipped with active park assist, GO to AK7.

AK5 CHECK THE WHEEL SPEED SENSOR CIRCUITS FOR AN OPEN

Ignition OFF.

For the LR wheel speed sensor, measure:

Positive Lead	Measurement / Action	Negative Lead
C135-36	Courtesy of FORD MOTOR COMPANY	C440-1
C135-37	Courtesy of FORD MOTOR COMPANY	C440-2

For the RR wheel speed sensor, measure:

Positive Lead	Measurement / Action	Negative Lead
C135-42	Courtesy of FORD MOTOR COMPANY	C426-2
C135-43	Courtesy of FORD MOTOR COMPANY	C426-1

Are the resistances less than 3 ohms?

Yes	GO to AK6.
No	REPAIR the circuit.

AK6 CHECK FOR SHORTED WHEEL SPEED SENSOR CIRCUITS

For the LR wheel speed sensor, measure:

Positive Lead	Measurement / Action	Negative Lead
C440-1	Courtesy of FORD MOTOR COMPANY	C440-2

For the RR wheel speed sensor, measure:

Positive Lead	Measurement / Action	Negative Lead
C426-1	Courtesy of FORD MOTOR COMPANY	C426-2

Is the resistance greater 10, 000 ohms?

Yes	GO to AK9.
No	REPAIR the circuit.

AK7 CHECK THE BI-DIRECTIONAL WHEEL SPEED SENSOR CIRCUITS FOR AN OPEN

Ignition OFF.

For the LR wheel speed sensor, measure:

Positive Lead	Measurement / Action	Negative Lead
C135-36	Courtesy of FORD MOTOR COMPANY	C4261-1
C135-37	Courtesy of FORD MOTOR COMPANY	C4261-2

For the RR wheel speed sensor, measure:

Positive Lead	Measurement / Action	Negative Lead
C135-42	Courtesy of FORD MOTOR COMPANY	C4260-2
C135-43	Courtesy of FORD MOTOR COMPANY	C4260-1

Are the resistances less than 3 ohms?

Yes	GO to AK8.
No	REPAIR the circuit.

AK8 CHECK FOR SHORTED BI-DIRECTIONAL WHEEL SPEED SENSOR CIRCUITS

For the LR wheel speed sensor, measure:

Positive Lead	Measurement / Action	Negative Lead
C4261-2	Courtesy of FORD MOTOR COMPANY	C4261-1

For the RR wheel speed sensor, measure:

Positive Lead	Measurement / Action	Negative Lead
C4260-2	Courtesy of FORD MOTOR COMPANY	C4260-1

Is the resistance greater 10, 000 ohms?

Yes	GO to AK9.
No	REPAIR the circuit.

AK9 CHECK THE WHEEL SPEED SENSOR CIRCUITS FOR A SHORT TO GROUND

For the LR wheel speed sensor, measure:

Positive Lead	Measurement / Action	Negative Lead
C135-36	Courtesy of FORD MOTOR COMPANY	Ground
C135-37	Courtesy of FORD MOTOR COMPANY	Ground

For the RR wheel speed sensor, measure:

Positive Lead	Measurement / Action	Negative Lead
C135-42	Courtesy of FORD MOTOR COMPANY	Ground
C135-43	Courtesy of FORD MOTOR COMPANY	Ground

Are the resistances greater than 10, 000 ohms?

Yes	For vehicles not equipped with active park assist, GO to AK10. For vehicles equipped with active park assist, GO to AK11.
No	REPAIR the circuit.

AK10 CHECK THE ABS MODULE OUTPUT

Ignition OFF.

Connect ABS module C135 .

Ignition ON.

For the LR wheel speed sensor, measure:

Positive Lead	Measurement / Action	Negative Lead
C440-1	Courtesy of FORD MOTOR COMPANY	C440-2

For the RR wheel speed sensor, measure:

Positive Lead	Measurement / Action	Negative Lead
C426-1	Courtesy of FORD MOTOR COMPANY	C426-2

Is the voltage greater than 10 volts?

Yes	INSTALL a new rear wheel speed sensor. REFER to Wheel Speed Sensor - Rear . CARRY OUT the following steps to clear the ABS module DTCs : DRIVE the vehicle at a speed greater than 20 km/h (12.4 mph), CYCLE the ignition from ON to OFF and back to ON, CLEAR the ABS module DTCs and CARRY OUT the ABS module self-test.
No	GO to AK12.

AK11 CHECK THE OUTPUT FROM THE ABS MODULE

Ignition OFF.

Connect ABS module C135 .

Ignition ON.

For the LR wheel speed sensor, measure:

Positive Lead	Measurement / Action	Negative Lead
C4260-1	Courtesy of FORD MOTOR COMPANY	C4260-2

For the RR wheel speed sensor, measure:

Positive Lead	Measurement / Action	Negative Lead
C4261-1	Courtesy of FORD MOTOR COMPANY	C4261-2

Is the voltage greater than 10 volts?

Yes	INSTALL a new rear wheel speed sensor. REFER to Wheel Speed Sensor - Rear . CARRY OUT the following steps to clear the ABS module DTCs : DRIVE the vehicle at a speed greater than 20 km/h (12.4 mph), CYCLE the ignition from ON to OFF and back to ON, CLEAR the ABS module DTCs and CARRY OUT the ABS module self-test.
No	GO to AK12.

AK12 CHECK FOR CORRECT ABS MODULE OPERATION

Inspect ABS module C135 .

Repair:
- 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

Connect ABS module C135 . Make sure it seats and latches correctly.

Connect wheel speed sensor C440 and C426 . Make sure they seat and latch correctly.

Operate the system and determine if the concern is still present.

Is the concern still present?

Yes

CHECK OASIS for any applicable TSBs. If a TSB exists for this concern, DISCONTINUE this test and FOLLOW the TSB instructions. On vehicles not equipped with adaptive cruise control, if no TSBs address this concern, INSTALL a new ABS module. REFER to Anti-Lock Brake System (ABS) Module . On vehicles equipped with adaptive cruise control, if no TSBs address this concern, INSTALL a new ABS module and HCU. REFER to Hydraulic Control Unit (HCU) .

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.