Lexus ES: Malfunction in Front Speed Sensor RH Circuit (C1401,C1402)

Lexus ES (XZ10) Service Manual / Brake / Brake Control / Dynamic Control Systems / Electronically Controlled Brake System (for Hv Model) / Malfunction in Front Speed Sensor RH Circuit (C1401,C1402)

DESCRIPTION

Refer to DTCs C1413 and C1414.

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DTC No.	Detection Item	INF Code	DTC Detection Condition	Trouble Area	MIL	Note
C1401	Malfunction in Front Speed Sensor RH Circuit	501 502 507	INF Code: 501 At a vehicle speed of 10 km/h (6 mph) or more, output voltage from one of the speed sensors is less than that from the other sensors for 15 seconds or more. INF Code: 502 At a vehicle speed of 10 km/h (6 mph) or more, outputs from both front speed sensors are 0 km/h (0 mph) for 15 seconds or more. (except when both rear speed sensors are 0 km/h (0 mph)). INF Code: 507 At a vehicle speed of 10 km/h (6 mph) or more, output from one of the speed sensors is 0 km/h (0 mph) for 1 second or more.	Front speed sensor RH Speed sensor installed improperly Front speed sensor rotor RH (front axle hub sub-assembly RH) Wire harness or connector	Comes on	INF Code 501: SAE Code C0507 (Case 1) INF Code 502: SAE Code C140C INF Code 507: SAE Code C0507 (Case 2) ABS DTC
C1402	Malfunction in Front Speed Sensor LH Circuit	511 512 517	INF Code: 511 At a vehicle speed of 10 km/h (6 mph) or more, output voltage from one of the speed sensors is less than that from the other sensors for 15 seconds or more. INF Code: 512 At a vehicle speed of 10 km/h (6 mph) or more, outputs from both front speed sensors are 0 km/h (0 mph) for 15 seconds or more. (except when both rear speed sensors are 0 km/h (0 mph)). INF Code: 517 At a vehicle speed of 10 km/h (6 mph) or more, output from one of the speed sensors is 0 km/h (0 mph) for 1 second or more.	Front speed sensor LH Speed sensor installed improperly Front speed sensor rotor LH (front axle hub sub-assembly LH) Wire harness or connector	Comes on	INF Code 511: SAE Code C0501 (Case 1) INF Code 512: SAE Code C140B INF Code 517: SAE Code C0501 (Case 2) ABS DTC

DTC No.

Detection Item

INF Code

DTC Detection Condition

Trouble Area

MIL

Note

C1401

Malfunction in Front Speed Sensor RH Circuit

501

502

507

INF Code: 501
- At a vehicle speed of 10 km/h (6 mph) or more, output voltage from one of the speed sensors is less than that from the other sensors for 15 seconds or more.
INF Code: 502
- At a vehicle speed of 10 km/h (6 mph) or more, outputs from both front speed sensors are 0 km/h (0 mph) for 15 seconds or more. (except when both rear speed sensors are 0 km/h (0 mph)).
INF Code: 507
- At a vehicle speed of 10 km/h (6 mph) or more, output from one of the speed sensors is 0 km/h (0 mph) for 1 second or more.

Front speed sensor RH
Speed sensor installed improperly
Front speed sensor rotor RH (front axle hub sub-assembly RH)
Wire harness or connector

Comes on

INF Code 501: SAE Code C0507 (Case 1)
INF Code 502: SAE Code C140C
INF Code 507: SAE Code C0507 (Case 2)
ABS DTC

C1402

Malfunction in Front Speed Sensor LH Circuit

511

512

517

INF Code: 511
- At a vehicle speed of 10 km/h (6 mph) or more, output voltage from one of the speed sensors is less than that from the other sensors for 15 seconds or more.
INF Code: 512
- At a vehicle speed of 10 km/h (6 mph) or more, outputs from both front speed sensors are 0 km/h (0 mph) for 15 seconds or more. (except when both rear speed sensors are 0 km/h (0 mph)).
INF Code: 517
- At a vehicle speed of 10 km/h (6 mph) or more, output from one of the speed sensors is 0 km/h (0 mph) for 1 second or more.

Front speed sensor LH
Speed sensor installed improperly
Front speed sensor rotor LH (front axle hub sub-assembly LH)
Wire harness or connector

Comes on

INF Code 511: SAE Code C0501 (Case 1)
INF Code 512: SAE Code C140B
INF Code 517: SAE Code C0501 (Case 2)
ABS DTC

MONITOR DESCRIPTION

When the vehicle is being driven, if the value of the speed sensor which is outputting the lowest vehicle speed is significantly lower than the values of the other speed sensors, or the value of the speed sensor which is outputting the lowest vehicle speed is 0 km/h (0 mph), the skid control ECU (brake booster with master cylinder assembly) judges that the speed sensor is malfunctioning and illuminates the MIL and stores a DTC.

Also, when a wheel speed is being output (the wheel is not locked), if the output values of the speed sensors for 2 wheels are stuck at 0 km/h (0 mph), the skid control ECU (brake booster with master cylinder assembly) judges that a speed sensor is malfunctioning and illuminates the MIL and stores a DTC.

MONITOR STRATEGY

Related DTCs	C0501 (Case 1): Speed sensor range/performance C0501 (Case 2): Speed sensor range/performance C0507 (Case 1): Speed sensor range/performance C0507 (Case 2): Speed sensor range/performance C140B: 2 wheel speed sensors malfunction C140C: 2 wheel speed sensors malfunction
Required Sensors/Components(Main)	Speed sensor Speed sensor rotor
Required Sensors/Components(Related)	Stop light switch assembly Parking brake switch assembly Brake actuator (brake booster with master cylinder assembly) Speed sensor
Frequency of Operation	Continuous
Duration	1 second: C0501 (Case 2) and C0507 (Case 2) 15 seconds: C0501 (Case 1), C0507 (Case 1), C140B and C140C
MIL Operation	Immediately
Sequence of Operation	None

TYPICAL ENABLING CONDITIONS

C0501 and C0507 (Case 1)

Monitor runs whenever the following DTCs are not stored	C0502, C0508, C050E, C0514 (Speed sensor circuit low) C0503, C0509, C050F, C0515 (Speed sensor circuit high) C0504, C050A, C0510, C0516 (Speed sensor intermittent/erratic) C051C (Case 1) (Acceleration sensor range/performance) C051C (Case 2) (Acceleration sensor range/performance) C051C (Case 3) (Acceleration sensor range/performance) C051C (Case 4) (Acceleration sensor range/performance) C051E (Acceleration sensor intermittent/erratic) C0520 (Case 1) (Acceleration sensor 2 out of range) C0520 (Case 2) (Acceleration sensor 1 and acceleration sensor 2 out of range) C0520 (Case 3) (Acceleration sensor internal malfunction) C052B (ABS pump motor range/performance) C052D (ABS pump motor circuit high) C052E (ABS pump motor open circuit) C0562 (Brake pedal stroke sensor assembly voltage circuit/open) C0594 (Pump motor performance) C0597 (Case 1) (EEPROM malfunction) C0597 (Case 2) (Lost communication) C0597 (Case 3) (CPU malfunction) C0597 (Case 4) (IC malfunction) C1202 (Brake master cylinder reservoir assembly level too low) C120F (Brake fluid level warning switch open circuit) C121D (Pump motor open circuit) C121E (Pump motor circuit high) C123B (IG1 circuit low) C123E (IG2 circuit low) C1240 (Yaw rate and acceleration sensor incorrect) C1241 (Case 1 to 11) (Brake system voltage circuit low) C124A (CAN communication identification signal) C124B (Brake pedal stroke sensor assembly invalid data) C1256 (Accumulator pressure too low) C12A6, C12BC, C12D2, C12E8 (ABS holding solenoid range/performance) C12A7, C12BD, C12D3, C12E9 (ABS holding solenoid circuit low) C12A8, C12BE, C12D4, C12EA (ABS holding solenoid circuit high) C12B2, C12C8, C12DE, C12F4 (ABS reduction solenoid circuit low) C12B3, C12C9, C12DF, C12F5 (ABS reduction solenoid circuit high) C12FA (Main relay circuit low) C12FB (Main relay circuit high) C1336 (Acceleration sensor exceeded learning limit) C1392 (Brake pedal stroke sensor learning not complete) C139A (One hydraulic path fail) C139D (Linear solenoid (SLA) stuck on) C13C1, C13CA, C14F2, C14FB (Linear solenoid range/performance) C13C2, C13CB, C14F3, C14FC (Linear solenoid circuit low) C13C3, C13CC, C14F4, C14FD (Linear solenoid circuit high) C13CD (Brake pressure too low) C13CE (Brake pressure too high) C1400 (ABS reduction solenoid leakage) C140B, C140C, C140D, C140E (2 wheel speed sensors malfunction) C1417 (Brake system voltage circuit high) C1427 (ABS pump motor stuck) C1451 (High pressure hydraulic tube air bleeding not complete) C146E (ABS solenoid power supply relay circuit low) C146F (ABS solenoid power supply relay circuit high) C14B0 (Reaction force pressure sensor voltage circuit check) C14B1 (Reaction force pressure sensor lost communication) C14B2 (Reaction force pressure sensor internal malfunction) C14B3 (Reaction force pressure sensor exceeded learning limit) C14B4 (Reaction force pressure sensor intermittent/erratic) C14B5 (Reaction force pressure sensor invalid data) C14B6 (Brake stroke/reaction force pressure correlation) C14C0 (Servo pressure sensor voltage circuit check) C14C1 (Servo pressure sensor lost communication) C14C2 (Servo pressure sensor internal malfunction) C14C3 (Servo pressure sensor exceeded learning limit) C14C4 (Servo pressure sensor intermittent/erratic) C14C5 (Servo pressure sensor invalid data) C14D0 (Accumulator pressure sensor voltage circuit check) C14D1 (Accumulator pressure sensor lost communication) C14D2 (Accumulator pressure sensor internal malfunction) C14D3 (Accumulator pressure sensor intermittent/erratic) C14D4 (Case 1) (Accumulator pressure sensor invalid data) C14D4 (Case 2) (Accumulator pressure sensor intermittent) C14D5 (Accumulator pressure sensor stuck) C14D7 (Acceleration sensor voltage circuit/open) C14DB (ABS solenoid power supply voltage circuit low) C14DE (Main relay voltage circuit low) C14DF (Main relay voltage circuit high) C14E1, C14E4, C14E7, C14EA (Case 1) (Speed sensor voltage circuit low) C14E1, C14E4, C14E7, C14EA (Case 2) (Speed sensor voltage circuit low) C14EE (Switching solenoid (SSA) stuck on) C14F7 (Switching solenoid (SGH) stuck on) P0572 (Stop light switch assembly open circuit) P0573 (Stop light switch assembly circuit high) P057C, P05DD (Brake pedal stroke sensor assembly open circuit) P057D, P05DE (Brake pedal stroke sensor assembly circuit high) P057E, P05DF (Brake pedal stroke sensor assembly intermittent/erratic) P05E0 (Brake pedal stroke sensor assembly "1"/"2" correlation) U0073 (Control module communication bus "A" off) U0074 (Control module communication bus "B" off) U0100 (Case 1) (Lost communication with ECM/PCM "A") U0110 (Case 1) (Lost communication with drive motor control module "A") U0125 (Lost communication with multi-axis acceleration sensor module) U0293 (Case 1) (Lost communication with hybrid powertrain control module)
All of the following conditions are met	-
Control valve solenoid	Non-drive
Brake system voltage 1 (VM1)	Less than 16.44 V
Difference between the highest speed sensor output value and the second lowest speed sensor output value	Less than 20% of the highest speed sensor output value
The second lowest speed sensor output value	10 km/h (6 mph) or more
Speed sensor fail (C0502, C0503, C0504, C0508, C0509, C050A, C050E, C050F, C0510, C0514, C0515, C0516, C14E1, C14E4, C14E7, C14EA)	Not detected

C0501 and C0507 (Case 2)

Monitor runs whenever the following DTCs are not stored	C0502, C0508, C050E, C0514 (Speed sensor circuit low) C0503, C0509, C050F, C0515 (Speed sensor circuit high) C0504, C050A, C0510, C0516 (Speed sensor intermittent/erratic) C051C (Case 1) (Acceleration sensor range/performance) C051C (Case 2) (Acceleration sensor range/performance) C051C (Case 3) (Acceleration sensor range/performance) C051C (Case 4) (Acceleration sensor range/performance) C051E (Acceleration sensor intermittent/erratic) C0520 (Case 1) (Acceleration sensor 2 out of range) C0520 (Case 2) (Acceleration sensor 1 and acceleration sensor 2 out of range) C0520 (Case 3) (Acceleration sensor internal malfunction) C052B (ABS pump motor range/performance) C052D (ABS pump motor circuit high) C052E (ABS pump motor open circuit) C0562 (Brake pedal stroke sensor assembly voltage circuit/open) C0594 (Pump motor performance) C0597 (Case 1) (EEPROM malfunction) C0597 (Case 2) (Lost communication) C0597 (Case 3) (CPU malfunction) C0597 (Case 4) (IC malfunction) C1202 (Brake master cylinder reservoir assembly level too low) C120F (Brake fluid level warning switch open circuit) C121D (Pump motor open circuit) C121E (Pump motor circuit high) C123B (IG1 circuit low) C123E (IG2 circuit low) C1240 (Yaw rate and acceleration sensor incorrect) C1241 (Case 1 to 11) (Brake system voltage circuit low) C124A (CAN communication identification signal) C124B (Brake pedal stroke sensor assembly invalid data) C1256 (Accumulator pressure too low) C12A6, C12BC, C12D2, C12E8 (ABS holding solenoid range/performance) C12A7, C12BD, C12D3, C12E9 (ABS holding solenoid circuit low) C12A8, C12BE, C12D4, C12EA (ABS holding solenoid circuit high) C12B2, C12C8, C12DE, C12F4 (ABS reduction solenoid circuit low) C12B3, C12C9, C12DF, C12F5 (ABS reduction solenoid circuit high) C12FA (Main relay circuit low) C12FB (Main relay circuit high) C1336 (Acceleration sensor exceeded learning limit) C1392 (Brake pedal stroke sensor learning not complete) C139A (One hydraulic path fail) C139D (Linear solenoid (SLA) stuck on) C13C1, C13CA, C14F2, C14FB (Linear solenoid range/performance) C13C2, C13CB, C14F3, C14FC (Linear solenoid circuit low) C13C3, C13CC, C14F4, C14FD (Linear solenoid circuit high) C13CD (Brake pressure too low) C13CE (Brake pressure too high) C1400 (ABS reduction solenoid leakage) C140B, C140C, C140D, C140E (2 wheel speed sensors malfunction) C1417 (Brake system voltage circuit high) C1427 (ABS pump motor stuck) C1451 (High pressure hydraulic tube air bleeding not complete) C146E (ABS solenoid power supply relay circuit low) C146F (ABS solenoid power supply relay circuit high) C14B0 (Reaction force pressure sensor voltage circuit check) C14B1 (Reaction force pressure sensor lost communication) C14B2 (Reaction force pressure sensor internal malfunction) C14B3 (Reaction force pressure sensor exceeded learning limit) C14B4 (Reaction force pressure sensor intermittent/erratic) C14B5 (Reaction force pressure sensor invalid data) C14B6 (Brake stroke/reaction force pressure correlation) C14C0 (Servo pressure sensor voltage circuit check) C14C1 (Servo pressure sensor lost communication) C14C2 (Servo pressure sensor internal malfunction) C14C3 (Servo pressure sensor exceeded learning limit) C14C4 (Servo pressure sensor intermittent/erratic) C14C5 (Servo pressure sensor invalid data) C14D0 (Accumulator pressure sensor voltage circuit check) C14D1 (Accumulator pressure sensor lost communication) C14D2 (Accumulator pressure sensor internal malfunction) C14D3 (Accumulator pressure sensor intermittent/erratic) C14D4 (Case 1) (Accumulator pressure sensor invalid data) C14D4 (Case 2) (Accumulator pressure sensor intermittent) C14D5 (Accumulator pressure sensor stuck) C14D7 (Acceleration sensor voltage circuit/open) C14DB (ABS solenoid power supply voltage circuit low) C14DE (Main relay voltage circuit low) C14DF (Main relay voltage circuit high) C14E1, C14E4, C14E7, C14EA (Case 1) (Speed sensor voltage circuit low) C14E1, C14E4, C14E7, C14EA (Case 2) (Speed sensor voltage circuit low) C14EE (Switching solenoid (SSA) stuck on) C14F7 (Switching solenoid (SGH) stuck on) P0572 (Stop light switch assembly open circuit) P0573 (Stop light switch assembly circuit high) P057C, P05DD (Brake pedal stroke sensor assembly open circuit) P057D, P05DE (Brake pedal stroke sensor assembly circuit high) P057E, P05DF (Brake pedal stroke sensor assembly intermittent/erratic) P05E0 (Brake pedal stroke sensor assembly "1"/"2" correlation) U0073 (Control module communication bus "A" off) U0074 (Control module communication bus "B" off) U0100 (Case 1) (Lost communication with ECM/PCM "A") U0110 (Case 1) (Lost communication with drive motor control module "A") U0125 (Lost communication with multi-axis acceleration sensor module) U0293 (Case 1) (Lost communication with hybrid powertrain control module)
All of the following conditions are met	-
Control valve solenoid	Non-drive
Brake system voltage 1 (VM1)	Less than 16.44 V
Stop light switch assembly	Off
Parking brake	Off
Difference between the highest speed sensor output value and the second lowest speed sensor output value	Less than 2 km/h (1 mph)
The second lowest speed sensor output value	10 km/h (6 mph) or more
Speed sensor fail (C0502, C0503, C0504, C0508, C0509, C050A, C050E, C050F, C0510, C0514, C0515, C0516, C14E1, C14E4, C14E7, C14EA)	Not detected

C140B and C140C

Monitor runs whenever the following DTCs are not stored	C0502, C0508, C050E, C0514 (Speed sensor circuit low) C0503, C0509, C050F, C0515 (Speed sensor circuit high) C0504, C050A, C0510, C0516 (Speed sensor intermittent/erratic) C14E1, C14E4, C14E7, C14EA (Case 1) (Speed sensor voltage circuit low) C14E1, C14E4, C14E7, C14EA (Case 2) (Speed sensor voltage circuit low)
All of the following conditions are met	-
Control valve solenoid	Non-drive
Brake system voltage 1 (VM1)	Less than 16.44 V
Stop light switch assembly	Off
Parking brake	Off
Difference in output of the speed sensor with the highest value and the output of the speed sensor with the second highest value	Less than 20% of the highest speed sensor output value
The second highest speed sensor output value	10 km/h (6 mph) or more
Speed sensor fail (C0502, C0503, C0504, C0508, C0509, C050A, C050E, C050F, C0510, C0514, C0515, C0516, C14E1, C14E4, C14E7, C14EA)	Not detected
Stop light switch assembly fail (P0572)	Not detected

TYPICAL MALFUNCTION THRESHOLDS

C0501 and C0507 (Case 1)

One-seventh of the second lowest speed sensor output value

Higher than the lowest speed sensor output value

C0501 and C0507 (Case 2)

The lowest speed sensor output value

0 km/h (0 mph)

C140B and C140C

The second lowest speed sensor output value

0 km/h (0 mph)

COMPONENT OPERATING RANGE

C0501 and C0507 (Case 1)

All of the following conditions are met	-
Control valve solenoid	Non-drive
Brake system voltage 1 (VM1)	Less than 16.44 V
Difference between the highest speed sensor output value and the second lowest speed sensor output value	Less than 20% of the highest speed sensor output value
The second lowest speed sensor output value	10 km/h (6 mph) or more
Speed sensor fail (C0502, C0503, C0504, C0508, C0509, C050A, C050E, C050F, C0510, C0514, C0515, C0516, C14E1, C14E4, C14E7, C14EA)	Not detected
Speed sensor pass flag	On

C0501 and C0507 (Case 2)

All of the following conditions are met	-
Control valve solenoid	Non-drive
Brake system voltage 1 (VM1)	Less than 16.44 V
Stop light switch assembly	Off
Parking brake	Off
Difference between the highest speed sensor output value and the second lowest speed sensor output value	Less than 2 km/h (1 mph)
The second lowest speed sensor output value	10 km/h (6 mph) or more
Speed sensor fail (C0502, C0503, C0504, C0508, C0509, C050A, C050E, C050F, C0510, C0514, C0515, C0516, C14E1, C14E4, C14E7, C14EA)	Not detected
Speed sensor pass flag	On

C140B and C140C

All of the following conditions are met	-
Control valve solenoid	Non-drive
Brake system voltage 1 (VM1)	Less than 16.44 V
Stop light switch assembly	Off
Parking brake	Off
Difference in output of the speed sensor with the highest value and the output of the speed sensor with the second highest value.	Less than 20% of the highest speed sensor output value
The second highest speed sensor output value	10 km/h (6 mph) or more
Speed sensor fail (C0502, C0503, C0504, C0508, C0509, C050A, C050E, C050F, C0510, C0514, C0515, C0516, C14E1, C14E4, C14E7, C14EA)	Not detected
Stop light switch assembly fail (P0572)	Not detected
Speed sensor pass flag	On

CONFIRMATION DRIVING PATTERN

Connect the Techstream to the DLC3.
Turn the power switch on (IG).
Turn the Techstream on.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Turn the power switch off.
Turn the power switch on (READY).
Turn the Techstream on.
Drive the vehicle straight at a speed of 15 km/h (9 mph) or more for 15 seconds or more.
Enter the following menus: Chassis / ABS/VSC/TRAC / Trouble Codes.
Read the DTCs.
HINT:
- If a DTC is output, the system is malfunctioning.
- If a DTC is not output, perform the following procedure.
If the DTCs are not output, perform a universal trip and check for permanent DTCs.
Click here
HINT:
- If a permanent DTC is output, the system is malfunctioning.
- If no permanent DTCs are output, the system is normal.

WIRING DIAGRAM

Refer to DTCs C1413 and C1414.

Click here

PROCEDURE

CHECK DTC

(a) Clear the DTCs.

Click here

Chassis > ABS/VSC/TRAC > Clear DTCs

(b) Turn the power switch off.

(d) Check if the same DTC is output.

Click here

Chassis > ABS/VSC/TRAC > Trouble Codes

Result	Proceed to
DTC C1401 is output.	A
DTC C1402 is output.	B

GO TO STEP 7

2.	CHECK FRONT SPEED SENSOR RH INSTALLATION

(a) Check the front speed sensor RH installation.

OK:

There is no clearance between the sensor and the front steering knuckle.

The installation bolt is tightened properly.

Torque

8.5 N*m (87 kgf*cm, 75 in.*lbf)

*1	Front Speed Sensor RH
*a	OK
*b	NG
*c	8.5 N*m
*d	No Clearance

REINSTALL OR REPLACE FRONT SPEED SENSOR RH

3.	CHECK FRONT SPEED SENSOR RH (CHECK FOR FOREIGN MATTER)

(a) Remove the front speed sensor RH.

Click here

(b) Check the front speed sensor tip RH.

OK:

The sensor tip is free of scratches, oil, and foreign matter.

NOTICE:

If there is oil or foreign matter on the front speed sensor RH, clean the front speed sensor RH.
If the front speed sensor RH is damaged, replace the front speed sensor RH with a new one.
Check the front speed sensor RH signal after cleaning or replacement.
Click here

CLEAN OR REPLACE FRONT SPEED SENSOR RH

4.	READ VALUE USING TECHSTREAM (FRONT SPEED SENSOR RH)

(a) Install the front speed sensor RH.

(b) Select the Data List on the Techstream.

Click here

Chassis > ABS/VSC/TRAC > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
FR Wheel Speed	Front speed sensor RH	Min.: 0 km/h (0 mph), Max.: 326.4 km/h (203 mph)	Vehicle stopped: 0 km/h (0 mph)	When driving at constant speed: No large fluctuations

Chassis > ABS/VSC/TRAC > Data List

Tester Display
FR Wheel Speed

OK:

The output value changes in accordance with the vehicle speed.

USE SIMULATION METHOD TO CHECK

5.	CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY - FRONT SPEED SENSOR RH)

(a) Turn the power switch off.

(b) Make sure that there is no looseness at the locking part and the connecting part of the connectors.

OK:

The connector is securely connected.

(d) Disconnect the A46 front speed sensor RH connector.

(e) Check both the connector case and the terminals for deformation and corrosion.

OK:

No deformation or corrosion.

(f) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection	Condition	Specified Condition
A45-3 (FR+) - A46-1 (FR+)	Always	Below 1 Ω
A45-3 (FR+) or A46-1 (FR+) - Body ground	Always	10 kΩ or higher
A45-4 (FR-) - A46-2 (FR-)	Always	Below 1 Ω
A45-4 (FR-) or A46-2 (FR-) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

6.	CHECK FRONT SPEED SENSOR ROTOR RH (CHECK FOR FOREIGN MATTER)

(a) Remove the front speed sensor RH and the component with the front speed sensor rotor RH.

for Front Speed Sensor RH: Click here

for Front Speed Sensor Rotor RH: Click here

(b) Check the front speed sensor rotor RH.

OK:

The front speed sensor rotor RH is free of scratches, oil, and foreign matter.

NOTICE:

If there is oil or foreign matter on the front speed sensor rotor RH, clean the front speed sensor rotor RH.
If the front speed sensor rotor RH is damaged, replace the front speed sensor rotor RH with a new one.
Check the front speed sensor RH signal after cleaning or replacement.
Click here

HINT:

The front speed sensor rotor RH is incorporated into the front axle hub sub-assembly RH.
If the front speed sensor rotor RH needs to be replaced, replace it together with the front axle hub sub-assembly RH.

Result	Proceed to
OK	A
NG (The front speed sensor rotor RH is damaged.)	B
NG (There is foreign matter on the front speed sensor rotor RH.)	C

REPLACE FRONT SPEED SENSOR RH

REPLACE FRONT AXLE HUB SUB-ASSEMBLY RH

CLEAN FRONT SPEED SENSOR ROTOR RH

7.	CHECK FRONT SPEED SENSOR LH INSTALLATION

(a) Check the front speed sensor LH installation.

OK:

There is no clearance between the sensor and the front steering knuckle.

The installation bolt is tightened properly.

Torque

8.5 N*m (87 kgf*cm, 75 in.*lbf)

*1	Front Speed Sensor LH
*a	OK
*b	NG
*c	8.5 N*m
*d	No Clearance

REINSTALL OR REPLACE FRONT SPEED SENSOR LH

8.	CHECK FRONT SPEED SENSOR LH (CHECK FOR FOREIGN MATTER)

(a) Remove the front speed sensor LH.

Click here

(b) Check the front speed sensor tip LH.

OK:

The sensor tip is free of scratches, oil, and foreign matter.

NOTICE:

If there is oil or foreign matter on the front speed sensor LH, clean the front speed sensor LH.
If the front speed sensor LH is damaged, replace the front speed sensor LH with a new one.
Check the front speed sensor LH signal after cleaning or replacement.
Click here

CLEAN OR REPLACE FRONT SPEED SENSOR LH

9.	READ VALUE USING TECHSTREAM (FRONT SPEED SENSOR LH)

(a) Install the front speed sensor LH.

(b) Select the Data List on the Techstream.

Click here

Chassis > ABS/VSC/TRAC > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
FL Wheel Speed	Front speed sensor LH	Min.: 0 km/h (0 mph), Max.: 326.4 km/h (203 mph)	Vehicle stopped: 0 km/h (0 mph)	When driving at constant speed: No large fluctuations

Chassis > ABS/VSC/TRAC > Data List

Tester Display
FL Wheel Speed

OK:

The output value changes in accordance with the vehicle speed.

USE SIMULATION METHOD TO CHECK

10.	CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY - FRONT SPEED SENSOR LH)

(a) Turn the power switch off.

(b) Make sure that there is no looseness at the locking part and the connecting part of the connectors.

OK:

The connector is securely connected.

(d) Disconnect the A48 front speed sensor LH connector.

(e) Check both the connector case and the terminals for deformation and corrosion.

OK:

No deformation or corrosion.

(f) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection	Condition	Specified Condition
A45-31 (FL+) - A48-1 (FL+)	Always	Below 1 Ω
A45-31 (FL+) or A48-1 (FL+) - Body ground	Always	10 kΩ or higher
A45-32 (FL-) - A48-2 (FL-)	Always	Below 1 Ω
A45-32 (FL-) or A48-2 (FL-) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

11.	CHECK FRONT SPEED SENSOR ROTOR LH (CHECK FOR FOREIGN MATTER)

(a) Remove the front speed sensor LH and the component with the front speed sensor rotor LH.

for Front Speed Sensor LH: Click here

for Front Speed Sensor Rotor LH: Click here

(b) Check the front speed sensor rotor LH.

OK:

The front speed sensor rotor LH is free of scratches, oil, and foreign matter.

NOTICE:

If there is oil or foreign matter on the front speed sensor rotor LH, clean the front speed sensor rotor LH.
If the front speed sensor rotor LH is damaged, replace the front speed sensor rotor LH with a new one.
Check the front speed sensor LH signal after cleaning or replacement.
Click here

HINT:

The front speed sensor rotor LH is incorporated into the front axle hub sub-assembly LH.
If the front speed sensor rotor LH needs to be replaced, replace it together with the front axle hub sub-assembly LH.

Result	Proceed to
OK	A
NG (The front speed sensor rotor LH is damaged.)	B
NG (There is foreign matter on the front speed sensor rotor LH.)	C

REPLACE FRONT SPEED SENSOR LH

REPLACE FRONT AXLE HUB SUB-ASSEMBLY LH

CLEAN FRONT SPEED SENSOR ROTOR LH

SEE MORE:

Precaution

PRECAUTION PRECAUTION FOR DISCONNECTING CABLE FROM NEGATIVE AUXILIARY BATTERY TERMINAL NOTICE: When disconnecting the cable from the negative (-) auxiliary battery terminal, initialize the following systems after the cable is reconnected. System Name See Procedure Lane Control System (for H

Precaution

PRECAUTION PRECAUTION FOR DISCONNECTING CABLE FROM NEGATIVE AUXILIARY BATTERY TERMINAL NOTICE: When disconnecting the cable from the negative (-) auxiliary battery terminal, initialize the following system(s) after the cable is reconnected. System See Procedure Lane Control System (for HV M

Lexus ES: Malfunction in Front Speed Sensor RH Circuit (C1401,C1402)

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Open or Short in Rear Speed Sensor RH Circuit (C1407,C1408)

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Precaution

Precaution