Visual Inspection And Diagnostic Pre-Checks

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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.

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: Anti-Lock Brake System-A (ABS-A) Module Connector - C135A

Courtesy of FORD MOTOR CO.

Harness Side

CIRCUIT AND PIN DESCRIPTION

Circuit

Fig 2: Anti-Lock Brake System-B (ABS-B) Module Connector - C135B

Courtesy of FORD MOTOR CO.

Harness Side

CIRCUIT AND PIN DESCRIPTION

Circuit

Fig 3: Left Rear Wheel Speed Sensor Connector - C440

Courtesy of FORD MOTOR CO.

Harness Side

CIRCUIT AND PIN DESCRIPTION

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 4: Right Rear Wheel Speed Sensor Connector - C426

Courtesy of FORD MOTOR CO.

Harness Side

CIRCUIT AND PIN DESCRIPTION

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)

N1: CHECK FOR WHEEL SPEED SENSOR TESTER

Check for wheel speed sensor tester.

Is the Rotunda Wheel Speed Sensor Tester special tool available?

Yes	No
Go to N9.	Go to N2.

N2: CHECK FOR FAULT REPEATABILITY

Ignition ON.
Using a diagnostic scan tool, clear the ABS module Diagnostic Trouble Codes (DTCs).
Ignition OFF.
Ignition ON.

Are any of the DTCs shown in the DTC Fault Trigger Conditions table present?

Yes	No
If ONLY C1A95:01 is present, Go to N3. For all other DTCs, Go to N4	The system is operating correctly at this time. INSPECT both rear 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. DRIVE the vehicle at a speed greater than 20 km/h (12 mph) to CLEAR the ABS module wheel speed sensor DTC s.

N3: DETERMINE WHICH WHEEL SPEED SENSOR IS AT FAULT

Using a diagnostic scan tool, access the ABS and monitor the LF_WSPD (SPD) PID.
Using a diagnostic scan tool, access the ABS and monitor the LR_WSPD (SPD) PID .
Using a diagnostic scan tool, access the ABS and monitor the RF_WSPD (SPD) PID .
Using a diagnostic scan tool, access the ABS and monitor the RR_WSPD (SPD) PID .

Is any voltage present?

Yes	No
Go to N4	PINPOINT TESTS M

N4: CHECK THE WHEEL SPEED SENSOR CIRCUITS FOR A SHORT TO BATTERY VOLTAGE

Ignition OFF.
Disconnect ABS Module C135 .
Disconnect the suspect wheel speed sensor.
Ignition ON.

For the left rear wheel speed sensor, measure the voltage between:

Positive Lead	Measurement / Action	Negative Lead
C440 Pin 2		Ground
C440 Pin 1		Ground

For the right rear wheel speed sensor, measure the voltage between:

Positive Lead	Measurement / Action	Negative Lead
C426 Pin 2		Ground
C426 Pin 1		Ground

Is any voltage present?

Yes	No
REPAIR the circuit. DRIVE the vehicle at a speed greater than 20 km/h (12 mph) to CLEAR the ABS module wheel speed sensor DTCs.	Go to N5

N5: CHECK THE WHEEL SPEED SENSOR CIRCUITS FOR A SHORT TO GROUND

If not done previously, put the ABS module in sleep mode by performing the following steps:
- With ALL doors closed, set the ignition from ON to OFF.
- Disconnect the diagnostic scan tool.
- Open the door, exit the vehicle and close the door.
- Wait a minimum of 90 seconds for the ABS module to enter sleep mode.
Ignition OFF.
Disconnect the ABS Module C135 (if not previously disconnected).
Disconnect the suspect wheel speed sensor, left rear wheel speed sensor C440 , or right rear wheel speed sensor C426 (if not previously disconnected).

For the left rear wheel speed sensor, measure the resistance between:

Positive Lead	Measurement / Action	Negative Lead
C440 Pin 1	Ω	Ground
C440 Pin 2	Ω	Ground

For the right rear wheel speed sensor, measure the resistance between:

Positive Lead	Measurement / Action	Negative Lead
C426 Pin 1	Ω	Ground
C426 Pin 2	Ω	Ground

Are the resistances greater than 10,000 ohms?

Yes	No
Go to N6.	REPAIR the circuit. DRIVE the vehicle at a speed greater than 20 km/h (12 mph) to CLEAR the ABS module wheel speed sensor DTCs.

N6: CHECK FOR SHORTED WHEEL SPEED SENSOR CIRCUITS

For the left rear wheel speed sensor, measure the resistance between:

Positive Lead	Measurement / Action	Negative Lead
C440 Pin 1	Ω	C440 Pin 2

For the right rear wheel speed sensor, measure the resistance between:

Positive Lead	Measurement / Action	Negative Lead
C426 Pin 1	Ω	C426 Pin 2

Are the resistances greater than 10,000 ohms?

Yes	No
Go to N7.	REPAIR the circuit. DRIVE the vehicle at a speed greater than 20 km/h (12 mph) to CLEAR the ABS module wheel speed sensor DTC s.

N7: CHECK THE WHEEL SPEED CIRCUITS FOR AN OPEN

For the left rear wheel speed sensor, measure the resistance between:

Positive Lead	Measurement / Action	Negative Lead
C135 Pin 38	Ω	C440 Pin 2
C135 Pin 37	Ω	C440 Pin 1

For the right rear wheel speed sensor, measure the resistance between:

Positive Lead	Measurement / Action	Negative Lead
C135 Pin 35	Ω	C426 Pin 2
C135 Pin 36	Ω	C426 Pin 1

Are the resistances less than 3 ohms?

Yes	No
Go to N8.	REPAIR the circuit. DRIVE the vehicle at a speed greater than 20 km/h (12 mph) to CLEAR the ABS module wheel speed sensor DTC s.

N8: CHECK THE ABS (ANTI-LOCK BRAKE SYSTEM) MODULE OUTPUT

Connect ABS module connector C135 . Make sure the connector seats and latches correctly.
Ignition ON.

For the left rear wheel speed sensor, measure the voltage between:

Positive Lead	Measurement / Action	Negative Lead
C440 Pin 1		C440 Pin 2

For the right rear wheel speed sensor, measure the voltage between:

Positive Lead	Measurement / Action	Negative Lead
C426 Pin 1		C426 Pin 2

Check the maximum recorded voltage on the meter.

Is the voltage greater 10 volts?

Yes	No
INSTALL a new Wheel Speed Sensor. REFER to REAR WHEEL SPEED SENSOR - RAPTOR DRIVE the vehicle at a speed greater than 20 km/h (12 mph) to CLEAR the ABS module wheel speed sensor DTC s.	Go to N13.

N9: CHECK THE ABS MODULE OUTPUT WITH THE SPECIAL TOOL

Set the transmission to NEUTRAL and position the vehicle on a hoist. Refer to JACKING AND LIFTING - OVERVIEW .
Make sure the special tool power switch is in the OFF position.
Ignition OFF.
Disconnect the suspect wheel speed sensor.
Connect the special tool to the wheel speed sensor and vehicle harness.
Set the special tool power switch to the ON position.
Ignition ON.
Observe the Vehicle Module Output LED.

Is the Vehicle Module Output LED illuminated green?

Yes	No
Go to N10.	REPAIR the circuit between the special tool and the ABS module. DRIVE the vehicle at a speed greater than 20 km/h (12 mph) to CLEAR the ABS module wheel speed sensor DTC s.

N10: CHECK THE SPECIAL TOOL SYSTEM POLARITY

Observe the Current Fault LED.

Is the Current Fault LED illuminated?

Yes	No
Go to N11.	Go to N12.

N11: RECHECK THE SPECIAL TOOL SYSTEM POLARITY

Toggle the special tool system polarity switch from the current position to the other position.
Observe the Current Fault LED.

Is the Current Fault LED illuminated?

Yes	No
INSTALL a new Wheel Speed Sensor. Refer to REAR WHEEL SPEED SENSOR - RAPTOR . DRIVE the vehicle at a speed greater than 20 km/h (12 mph) to CLEAR the ABS module wheel speed sensor DTC s.	Go to N12.

N12: CHECK THE WHEEL SPEED SENSOR

Raise the vehicle on the hoist until the wheels can spin freely.
Refer to JACKING AND LIFTING - OVERVIEW .
Slowly spin the suspect wheel while observing the High and Low Sensor Output LED s, the Current Fault LED and the Air Gap LED.

Do the High and Low Sensor Output LEDs illuminate and flash?

Yes	No
Go to N13.	DRIVE the vehicle at a speed greater than 20 km/h (12 mph) to CLEAR the ABS module wheel speed sensor DTC s. If neither of the High or Low LEDs illuminate, The wheel speed sensor is open internally. INSTALL a new wheel speed sensor. REFER to REAR WHEEL SPEED SENSOR - RAPTOR . If only one of the High or Low LEDs illuminates, The wheel speed sensor is stuck in one state. INSTALL a new wheel speed sensor. REFER to REAR WHEEL SPEED SENSOR - RAPTOR . If the Current Fault LED is red, The wheel speed sensor is shorted. INSTALL a new wheel speed sensor. REFER to REAR WHEEL SPEED SENSOR - RAPTOR . If the Air Gap LED is illuminated red, The wheel speed sensor is out of range from the encoder ring. CHECK for obstructions between wheel speed sensor and the encoder ring. If the Air Gap LED flashes, The wheel speed sensor is near the edge of the acceptable range. CHECK for obstructions between wheel speed sensor and the encoder ring.

Yes

Go to N13.

DRIVE the vehicle at a speed greater than 20 km/h (12 mph) to CLEAR the ABS module wheel speed sensor DTC s.
If neither of the High or Low LEDs illuminate, The wheel speed sensor is open internally. INSTALL a new wheel speed sensor. REFER to REAR WHEEL SPEED SENSOR - RAPTOR .
If only one of the High or Low LEDs illuminates, The wheel speed sensor is stuck in one state.
INSTALL a new wheel speed sensor. REFER to REAR WHEEL SPEED SENSOR - RAPTOR .
If the Current Fault LED is red, The wheel speed sensor is shorted. INSTALL a new wheel speed sensor. REFER to REAR WHEEL SPEED SENSOR - RAPTOR .
If the Air Gap LED is illuminated red, The wheel speed sensor is out of range from the encoder ring. CHECK for obstructions between wheel speed sensor and the encoder ring.
If the Air Gap LED flashes, The wheel speed sensor is near the edge of the acceptable range. CHECK for obstructions between wheel speed sensor and the encoder ring.

N13: VERIFY ALL WIRING CONNECTIONS

Ignition OFF.
Disconnect the Rotunda Wheel Speed Sensor Tester special tool.
Disconnect ABS module connector C135 (If not previously disconnected).
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 N14	REPAIR the affected connectors or terminals. Refer to CONNECTOR REPAIR PROCEDURES for schematic and connector information. DRIVE the vehicle at a speed greater than 20km/h (12 mph) to CLEAR the ABS module wheel speed sensor DTC s.

N14: CHECK FOR CORRECT ABS MODULE OPERATION

Connect ABS module connector C135 . Make sure the connector seat and latches correctly.
Connect the wheel speed sensor electrical connector(s). Make sure the connector(s) seat and latches correctly.
Operate the system and determine if the concern is still present. Drive the vehicle at a speed greater than 20 km/h (12 mph) to clear the ABS module wheel speed sensor DTC s .

Is the concern still present?

Yes	No
CHECK OASIS for any applicable 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 service articles address this concern, INSTALL a new EBB module. REFER to ELECTRIC BRAKE BOOSTER (EBB) .	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.