Lexus ES: Control Module Communication Bus Off (U0073,U0100,U0126,U0129)

Lexus ES (XZ10) Service Manual / Drivetrain / Gf1a (transfer / 4wd / Awd) / Dynamic Torque Control Awd System / Control Module Communication Bus Off (U0073,U0100,U0126,U0129)

DESCRIPTION

The 4WD ECU assembly inputs the signals sent from the ECM, skid control ECU (brake actuator assembly) and steering sensor via CAN communication.

When DTCs indicating a CAN communication system malfunction are output, repair the CAN communication system before repairing each corresponding sensor.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area
U0073	Control Module Communication Bus Off	When the following continues for 5 seconds or more: Signals from the 4WD ECU assembly are not received. When the following occurs 10 times consecutively: A communication malfunction (bus off) occurs one or more times within 0.1 seconds.	CAN communication system 4WD ECU assembly
U0100	Lost Communication with ECM / PCM "A"	When both of the following continue for 2 seconds or more: The voltage of the IG1 terminal is 10 V or more. At a vehicle speed of 60 km/h (38 mph) or more, communication with the ECM cannot be performed.	CAN communication system 4WD ECU assembly ECM
U0126	Lost Communication with Steering Angle Sensor Module	When both of the following continue for 1 second or more: The voltage of the IG1 terminal is 10 V or more. Communication with the steering sensor cannot be performed. When all of the following occur 10 times or more within 60 seconds: The voltage of the IG1 terminal is 10 V or more. The condition that communication with the steering sensor cannot be performed occurs once within 5 seconds.	CAN communication system 4WD ECU assembly Steering sensor
U0129	Lost Communication with Brake System Control Module	When both of the following continue for 3 seconds or more: The voltage of the IG1 terminal is 10 V or more. Communication with the skid control ECU (brake actuator assembly) cannot be performed.	CAN communication system 4WD ECU assembly Skid control ECU (brake actuator assembly)

DTC Detection Conditions: U0073

		Vehicle Condition
		Pattern 1	Pattern 2
Diagnosis Condition	One or more times within 0.1 seconds.	-	○
Malfunction Status	Signals from the 4WD ECU assembly are not received.	○	-
Malfunction Status	A communication malfunction (bus off) occurs.	-	○
Detection Time		5 seconds or more	10 times consecutively
Number of Trips		1 trip	1 trip

DTC Detection Conditions: U0126

		Vehicle Condition
		Pattern 1	Pattern 2
Diagnosis Condition	The voltage of the IG1 terminal is 10 V or more.	○	○
Malfunction Status	Communication with the steering sensor cannot be performed.	○	-
Malfunction Status	The condition that communication with the steering sensor cannot be performed occurs once within 5 seconds.	-	○
Detection Time		1 second or more	10 times or more within 60 seconds
Number of Trips		1 trip	1 trip

PROCEDURE

1.	CHECK FOR DTC

(a) Check for DTCs.

Chassis > Four Wheel Drive > Trouble Codes

(b) Record the output DTCs (dynamic torque control AWD system).

HINT:

When DTCs indicating a CAN communication system malfunction are output, repair the CAN communication system before repairing each corresponding sensor.

GO TO CAN COMMUNICATION SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING)

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Lexus ES: Control Module Communication Bus Off (U0073,U0100,U0126,U0129)

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