Toyota 4Runner: Front Vertical Sensor Malfunction (B2652)

Toyota 4Runner Service Manual / Vehicle Interior / Seat / Front Power Seat Control System(w/ Memory) / Front Vertical Sensor Malfunction (B2652)

DESCRIPTION

When the front power seat switch LH does not receive a sensor signal despite upward or downward movement of the front of the seat cushion by power seat motor operation, this DTC is stored.

DTC Code	DTC Detection Condition	Trouble Area
B2652	The upward and downward lock detection position of the sensor is the same.	Front power seat switch LH Separate type front seat cushion Spring assembly LH (Front vertical motor) Harness or connector

WIRING DIAGRAM

PROCEDURE

1.	PERFORM ACTIVE TEST USING TECHSTREAM (POWER SEAT MOTOR FUNCTION)

(a) Select the Active Test, use the Techstream to generate a control command, and then check the power seat motor function (See page ).

Driver Seat

Tester Display	Test Part	Control Range	Diagnostic Note
Front Vertical Operation	Seat front vertical operation	Up / OFF / Down	-

OK:

Motor operates normally.

GO TO STEP 5

2.	CHECK FRONT POWER SEAT SWITCH LH (FRONT VERTICAL MOTOR CIRCUIT)

(a) Disconnect the b16 front vertical motor connector.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
b16-2 (O/P) - b16-3 (GND)	Front vertical switch on	4.8 to 5.1 V

Text in Illustration

*a	Front view of wire harness connector (to Separate Type Front Seat Cushion Spring Assembly LH [Front Vertical Motor])

GO TO STEP 4

3.	CHECK SEPARATE TYPE FRONT SEAT CUSHION SPRING ASSEMBLY LH (FRONT VERTICAL MOTOR)

(a) Connect the b16 front vertical motor connector.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
b16-2 (O/P) - Body ground	Front vertical switch on	4.5 to 4.8 V

Text in Illustration

*a	Component with harness connected (Separate Type Front Seat Cushion Spring Assembly LH [Front Vertical Motor])

REPLACE FRONT POWER SEAT SWITCH LH

REPLACE SEPARATE TYPE FRONT SEAT CUSHION SPRING ASSEMBLY LH (FRONT VERTICAL MOTOR)

4.	CHECK HARNESS AND CONNECTOR (FRONT POWER SEAT SWITCH LH - FRONT VERTICAL MOTOR)

(a) Disconnect the b19 front power seat switch LH connector.

(b) Disconnect the b16 front vertical motor connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
b19-3 (SSFV) - b16-2 (O/P)	Always	Below 1 Ω
b19-1 (SGND) - b16-3 (GND)	Always	Below 1 Ω
b19-3 (SSFV) - Body ground	Always	10 kΩ or higher
b19-1 (SGND) - Body ground	Always	10 kΩ or higher

REPLACE FRONT POWER SEAT SWITCH LH

REPAIR OR REPLACE HARNESS OR CONNECTOR

5.	INSPECT SEPARATE TYPE FRONT SEAT CUSHION SPRING ASSEMBLY LH (FRONT VERTICAL MOTOR)

(a) Remove the separate type front seat cushion spring assembly LH (front vertical motor) (See page ).

(b) Disconnect the b16 front vertical motor.

(c) Check if the seat cushion spring moves smoothly when the battery is connected to the front vertical motor connector terminals.

OK:

Measurement Condition	Operational Direction
Battery positive (+) → 4 (UP) Battery negative (-) → 1 (DOWN)	Seat cushion spring moves upward
Battery positive (+) → 1 (DOWN) Battery negative (-) → 4 (UP)	Seat cushion spring moves downward

Measurement Condition

Operational Direction

Battery positive (+) → 4 (UP)

Battery negative (-) → 1 (DOWN)

Seat cushion spring moves upward

Battery positive (+) → 1 (DOWN)

Battery negative (-) → 4 (UP)

Seat cushion spring moves downward

Text in Illustration

*a	Component without harness connected (Separate Type Front Seat Cushion Spring Assembly LH [Front Vertical Motor])

REPLACE SEPARATE TYPE FRONT SEAT CUSHION SPRING ASSEMBLY LH (FRONT VERTICAL MOTOR)

6.	CHECK HARNESS AND CONNECTOR (FRONT POWER SEAT SWITCH LH - FRONT VERTICAL MOTOR)

(a) Disconnect the b18 front power seat switch LH connector.

(b) Disconnect the b16 front vertical motor connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
b18-8 (FRV+) - b16-4 (UP)	Always	Below 1 Ω
b18-5 (FRV-) - b16-1 (DOWN)	Always	Below 1 Ω
b18-8 (FRV+) - Body ground	Always	10 kΩ or higher
b18-5 (FRV-) - Body ground	Always	10 kΩ or higher

REPLACE FRONT POWER SEAT SWITCH LH

REPAIR OR REPLACE HARNESS OR CONNECTOR

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