Toyota 4Runner: Open or Short in Front Speed Sensor RH Circuit (C1405,C1406)

Toyota 4Runner Service Manual / Brake / Brake Control / Dynamic Control Systems / Vehicle Stability Control System(for Hydraulic Brake Booster) / Open or Short in Front Speed Sensor RH Circuit (C1405,C1406)

DESCRIPTION

Refer to DTCs C1401 and C1402 (See page ).

DTC Code	DTC Detection Condition	Trouble Area
C1405 C1406	Either condition is met: An open in the speed sensor signal circuit continues for 0.5 seconds or more. With the IG1 terminal voltage at 9.5 V or higher, the sensor power supply voltage decreases for 0.5 seconds or more.	Front speed sensor RH/LH Skid control sensor wire Speed sensor circuit Master cylinder solenoid (Skid control ECU)

DTC Code

DTC Detection Condition

Trouble Area

C1405

C1406

Either condition is met:

An open in the speed sensor signal circuit continues for 0.5 seconds or more.
With the IG1 terminal voltage at 9.5 V or higher, the sensor power supply voltage decreases for 0.5 seconds or more.

Front speed sensor RH/LH
Skid control sensor wire
Speed sensor circuit
Master cylinder solenoid (Skid control ECU)

HINT:

DTC C1405 is for the front speed sensor RH.
DTC C1406 is for the front speed sensor LH.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

When replacing the master cylinder solenoid, perform calibration (See page ).

Check the speed sensor signal after replacement (See page ).

PROCEDURE

1.	CHECK HARNESS AND CONNECTOR (MOMENTARY INTERRUPTION)

(a) Using the Techstream, check for any momentary interruption in the wire harness and connector corresponding to the DTC (See page
).

ABS/VSC/TRAC

Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
FR Speed Open	Front speed sensor RH open detection/ Error or Normal	Normal	-
FL Speed Open	Front speed sensor LH open detection/ Error or Normal	Normal	-

OK:

Normal (there are no momentary interruptions).

HINT:

Perform the above inspection before removing the sensor and connector.

GO TO STEP 4

2.	READ VALUE USING TECHSTREAM (FRONT SPEED SENSOR)

GO TO STEP 4

3.	RECONFIRM DTC

(a) Clear the DTCs (See page ).

(b) Turn the ignition switch off.

(d) Drive the vehicle at a speed of 40 km/h (25 mph) or more for at least 60 seconds.

(e) Check if the same DTC is output (See page
).

Result

Result	Proceed to
DTCs C1405 and C1406 are not output	A
DTCs C1405 and/or C1406 are output	B

USE SIMULATION METHOD TO CHECK

REPLACE MASTER CYLINDER SOLENOID

4.	INSPECT SKID CONTROL SENSOR WIRE

(a) Remove the skid control sensor wire (See page ).

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

Standard Resistance:

for RH

Tester Connection	Condition	Specified Condition
Az2-1 - z5-1 (FR-)	Always	Below 1 Ω
Az2-2 - z5-2 (FR+)	Always	Below 1 Ω
Az2-1 - Az2-2	Always	10 kΩ or higher

for LH

Tester Connection	Condition	Specified Condition
Az3-1 - z6-1 (FL-)	Always	Below 1 Ω
Az3-2 - z6-2 (FL+)	Always	Below 1 Ω
Az3-1 - Az3-2	Always	10 kΩ or higher

Text in Illustration

*A	for RH
*B	for LH
*1	Skid Control Sensor Wire

REPLACE SKID CONTROL SENSOR WIRE

5.	CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - FRONT SPEED SENSOR)

(a) Install the skid control sensor wire.

(b) Disconnect the A6 skid control ECU connector.

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

Standard Resistance:

for RH

Tester Connection	Condition	Specified Condition
A6-3 (FR+) - z5-2 (FR+)	Always	Below 1 Ω
A6-3 (FR+) - Body ground	Always	10 kΩ or higher
A6-17 (FR-) - z5-1 (FR-)	Always	Below 1 Ω
A6-17 (FR-) - Body ground	Always	10 kΩ or higher

for LH

Tester Connection	Condition	Specified Condition
A6-18 (FL+) - z6-2 (FL+)	Always	Below 1 Ω
A6-18 (FL+) - Body ground	Always	10 kΩ or higher
A6-4 (FL-) - z6-1 (FL-)	Always	Below 1 Ω
A6-4 (FL-) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

6.	CHECK TERMINAL VOLTAGE (FR+, FL+)

(a) Disconnect the z5 and/or z6 front speed sensor connector.

(b) Connect the A6 skid control ECU connector.

Standard Voltage:

for RH

Tester Connection	Switch Condition	Specified Condition
z5-2 (FR+) - Body ground	Ignition switch ON	11 to 14 V

for LH

Tester Connection	Switch Condition	Specified Condition
z6-2 (FL+) - Body ground	Ignition switch ON	11 to 14 V

Text in Illustration

for RH

for LH

Front view of wire harness connector

(to Front Speed Sensor)

REPLACE FRONT SPEED SENSOR

REPLACE MASTER CYLINDER SOLENOID

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