Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: ABS Malfunction (C1296)

Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual / Drivetrain / Mf1a (transfer / 4wd / Awd) / Dynamic Torque Control Awd System / ABS Malfunction (C1296)

DESCRIPTION

If a malfunction in the speed sensor signal circuit or acceleration sensor (airbag sensor assembly*1 or yaw rate sensor assembly*2) circuit is detected, the 4WD ECU assembly stores this DTC.

The airbag sensor assembly has a built-in acceleration sensor.*1

DTC No.	Detection Item	DTC Detection Condition	Trouble Area
C1296	ABS Malfunction	When one of the following conditions is met: A wheel speed sensor malfunction is received from the skid control ECU (brake actuator assembly) An acceleration sensor (airbag sensor assembly1 or yaw rate sensor assembly2) malfunction is received from skid control ECU (brake actuator assembly)	Vehicle stability control system (Speed sensor circuit) Skid control ECU (Brake actuator assembly) Acceleration sensor (airbag sensor assembly) circuit1 Acceleration sensor (yaw rate sensor assembly) circuit2 4WD ECU assembly

*1: w/ Optitron Meter Type
*2: w/ TFT Meter Type

WIRING DIAGRAM

Refer to DTC C1337.

Click here

CAUTION / NOTICE / HINT

NOTICE:

When the 4WD ECU assembly is replaced with a known good one from another vehicle, it is necessary to perform calibration.

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HINT:

Check the condition of each related circuit connector before troubleshooting.

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PROCEDURE

1.	CHECK FOR DTC (VEHICLE STABILITY CONTROL SYSTEM)

(a) Clear the DTCs.

Chassis > Brake/EPB > Clear DTCs

(b) Turn the engine switch off.

(c) Drive the vehicle, accelerate to a speed of 20 km/h (12 mph) or more, and check if any DTCs related to a speed sensor or acceleration sensor are output.

Chassis > Brake/EPB > Trouble Codes

Result	Proceed to
Vehicle stability control system DTC (speed sensor or acceleration sensor DTC) is not output	A
Vehicle stability control system DTC (speed sensor or acceleration sensor DTC) is output	B

REPAIR CIRCUIT INDICATED BY OUTPUT CODE (VEHICLE STABILITY CONTROL SYSTEM)

2.	READ VALUE USING TECHSTREAM (WHEEL SPEED)

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(d) Enter the following menus: Chassis / Four Wheel Drive / Data List.

(e) Read the value displayed on the Techstream.

Chassis > Four Wheel Drive > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
FR Wheel Speed	Front wheel speed sensor RH reading	Min.: 0 km/h (0 mph) Max.: 326 km/h (202 mph)	Vehicle stopped: 0 km/h (0 mph)	No large fluctuations when driving at a constant speed.
FL Wheel Speed	Front wheel speed sensor LH reading	Min.: 0 km/h (0 mph) Max.: 326 km/h (202 mph)	Vehicle stopped: 0 km/h (0 mph)	No large fluctuations when driving at a constant speed.
RR Wheel Speed	Rear wheel speed sensor RH reading	Min.: 0 km/h (0 mph) Max.: 326 km/h (202 mph)	Vehicle stopped: 0 km/h (0 mph)	No large fluctuations when driving at a constant speed.
RL Wheel Speed	Rear wheel speed sensor LH reading	Min.: 0 km/h (0 mph) Max.: 326 km/h (202 mph)	Vehicle stopped: 0 km/h (0 mph)	No large fluctuations when driving at a constant speed.

Chassis > Four Wheel Drive > Data List

Tester Display
FR Wheel Speed
FL Wheel Speed
RR Wheel Speed
RL Wheel Speed

OK:

The speed value output from the speed sensor displayed on the Techstream is the same as the actual vehicle speed measured using a speedometer tester (calibrated chassis dynamometer).

GO TO VEHICLE STABILITY CONTROL SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING)

3.	READ VALUE USING TECHSTREAM (FORWARD AND REARWARD G)

(a) Enter the following menus: Chassis / Four Wheel Drive / Data List.

(b) Read the value displayed on the Techstream.

Chassis > Four Wheel Drive > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Forward and Rearward G	Forward and Rearward G	Min.: -25.10 m/s2 Max.: 24.90 m/s2	During acceleration/deceleration: Changes in accordance with acceleration	-

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Forward and Rearward G

Min.: -25.10 m/s2

Max.: 24.90 m/s2

During acceleration/deceleration: Changes in accordance with acceleration

Chassis > Four Wheel Drive > Data List

Tester Display
Forward and Rearward G

OK:

The acceleration sensor (airbag ECU assembly*1 or yaw rate sensor assembly*2) output value is normal.

*1: w/ Optitron Meter Type
*2: w/ TFT Meter Type

REPLACE 4WD ECU ASSEMBLY

GO TO VEHICLE STABILITY CONTROL SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING)

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Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: ABS Malfunction (C1296)

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