Lexus NX: Yaw Rate Sensor (C1234,C1243-C1245,C1279)

Lexus NX Service Manual / Brake / Brake Control / Dynamic Control Systems / Electronically Controlled Brake System / Yaw Rate Sensor (C1234,C1243-C1245,C1279)

DESCRIPTION

The skid control ECU (brake booster with master cylinder assembly) receives signals from the yaw rate and acceleration sensor (airbag ECU assembly) via CAN communication.

The airbag ECU assembly has a built-in yaw rate and acceleration sensor and detects the vehicle condition using 2 circuits (GL1, GL2).

If there are malfunctions in the bus lines between the yaw rate and acceleration sensor (airbag ECU assembly) and the CAN communication system, DTCs U0123 (Lost Communication With Yaw Rate Sensor Module) and U0124 (Lost Communication With Lateral Acceleration Sensor Module) will be stored.

These DTCs are also output when zero point calibration has not been completed.

DTC C1279 will be cleared when the yaw rate and acceleration sensor (airbag ECU assembly) sends a yaw rate and/or acceleration signal or when Test Mode ends. DTC C1279 is output only in Test Mode.

DTC No.	Detection Item	INF Code	DTC Detection Condition	Trouble Area	Note
C1234	Yaw Rate Sensor	711 712 713 714	INF Code: 711 While yaw rate sensor communication is enabled, a malfunction signal is received during the sensor self-check (Sensor 1 (GL1) malfunction). INF Code: 712 While yaw rate sensor communication is enabled, a malfunction signal is received during the sensor self-check (Sensor 2 (GL2) malfunction). INF Code: 713 While yaw rate sensor communication is enabled, a malfunction signal is received during the sensor self-check (Zero point calibration malfunction). INF Code: 714 While yaw rate sensor communication is enabled, a malfunction signal is received during the sensor self-check (Two-value comparison malfunction).	Yaw rate sensor (Airbag ECU assembly) internal malfunction	-
C1243	Deceleration Sensor Stuck	561 562 563 564 565	INF Code: 561 An acceleration sensor malfunction occurs 16 times or more when the vehicle speed drops from above 30 km/h (19 mph) to 0 km/h (0 mph). INF Code: 562, 563, 564, 565 A stuck acceleration sensor value is determined.	Acceleration sensor (Airbag ECU assembly) internal stuck malfunction	-
C1244	Open or Short Circuit in Deceleration Sensor Circuit	571	Either of the following is detected: Difference between GL1 and GL2 does not become less than 0.4 G for 60 seconds or more after reaching 0.6 G when the vehicle is stopped. A malfunction signal from the acceleration sensor is received.	Acceleration sensor (Airbag ECU assembly) installed improperly Acceleration sensor (Airbag ECU assembly)	-
C1245	Abnormal Output in Deceleration Sensor	581	At a vehicle speed of 30 km/h (19 mph) or more, difference between longitudinal G calculated from the acceleration sensor value and that calculated from the vehicle speed exceeds 0.35 G for 60 seconds or more.	Acceleration sensor (Airbag ECU assembly) installed improperly Acceleration sensor (Airbag ECU assembly)	-
C1279	Abnormal Output Voltage in Deceleration Sensor	-	Detected only during Test Mode.	Sensor installation Acceleration sensor (Airbag ECU assembly)	-

CAUTION / NOTICE / HINT

NOTICE:

When replacing the yaw rate and acceleration sensor (airbag ECU assembly), perform zero point calibration.

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HINT:

When U0123 and/or U0124 is output together with C1234, C1243, C1244, and/or C1245, inspect and repair the trouble areas indicated by U0123 and/or U0124 first.

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PROCEDURE

CHECK DTC

(a) Clear the DTCs.

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Chassis > ABS/VSC/TRAC > Clear DTCs

(b) Turn the power switch off.

(d) Drive the vehicle at a speed of 30 km/h (19 mph) or more, turn the steering wheel, and decelerate (depress the brake pedal) the vehicle.

(e) Turn the power switch on (IG) again and check that no CAN communication system DTCs are output.

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(f) Check if DTC C1210 (Zero Point Calibration of Yaw Rate Sensor undone) or C1336 (Zero Point Calibration of Deceleration Sensor undone) is output.

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Chassis > ABS/VSC/TRAC > Trouble Codes

Result	Proceed to
DTCs (C1210, C1336 and CAN communication system DTCs) are not output.	A
CAN communication system DTCs are output.	B
DTCs C1210 and/or C1336 are output.	C

INSPECT CAN COMMUNICATION SYSTEM

REPAIR CIRCUITS INDICATED BY OUTPUT DTCS

2.	CHECK AIRBAG ECU ASSEMBLY INSTALLATION

(a) Turn the power switch off.

(b) Check that the yaw rate and acceleration sensor (airbag ECU assembly) has been installed properly.

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OK:

The airbag ECU assembly is tightened to the specified torque.

The airbag ECU assembly is not tilted.

NOTICE:

Check the yaw rate and acceleration sensor (airbag ECU assembly) signal after replacement.

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HINT:

If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step.

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REPLACE AIRBAG ECU ASSEMBLY

INSTALL AIRBAG ECU ASSEMBLY CORRECTLY

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Operation Check

OPERATION CHECK AUTOMATIC LIGHT CONTROL SYSTEM OPERATION CHECK (a) Turn the power switch on (IG). (b) Turn the headlight dimmer switch to the AUTO position. (c) Cover the automatic light control sensor. (d) Check that the taillights and low beam headlights come on. (e) Uncover the automatic light co

GVIF Disconnected (from EMV/MM Integrated Device to Multi Display) (B1575)

DESCRIPTION DTC No. Detection Item DTC Detection Condition Trouble Area B1575 GVIF Disconnected (from EMV/MM Integrated Device to Multi Display) GVIF disconnected (from radio receiver assembly to multi-display assembly) Harness or connector (GVIF cable) Multi-display assembly

Lexus NX: Yaw Rate Sensor (C1234,C1243-C1245,C1279)

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Operation Check

GVIF Disconnected (from EMV/MM Integrated Device to Multi Display) (B1575)