Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual: Control Module Communication Bus Off (U0073)

Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual / Drivetrain / Mf1a (transfer / 4wd / Awd) / Dynamic Torque Control Awd System / Control Module Communication Bus Off (U0073)

DESCRIPTION

The 4WD ECU assembly stores this DTC when a communication malfunction is detected.

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

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.

Click here

PROCEDURE

1.

CHECK CAN COMMUNICATION SYSTEM

(a) Check for malfunctions in the CAN communication system.

Click here

Result

Proceed to

CAN communication DTCs are not output

A

CAN communication DTCs are output

B
B

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

A

2.

RECONFIRM DTC

(a) Clear the DTCs.

Click here

Chassis > Four Wheel Drive > Clear DTCs

(b) Turn the engine switch off.

(c) Check if the same DTC is output.

Click here

Chassis > Four Wheel Drive > Trouble Codes

Result

Proceed to

DTC U0073 is output

A

DTC U0073 is not output

B
A

REPLACE 4WD ECU ASSEMBLY

B

CHECK FOR INTERMITTENT PROBLEMS

    Diameter of the Tire is not Uniform (C1337)
    DESCRIPTION The 4WD ECU assembly stores this DTC if a difference in tire size is detected. DTC No. Detection Item DTC Detection Condition Trouble Area C1337 Diameter of the Tire is not ...

    Lost Communication with ECM / PCM "A" (U0100,U0126,U0129)
    DESCRIPTION The 4WD ECU assembly receives signals from the ECM, skid control ECU (brake actuator assembly) and steering sensor via CAN communication. When DTCs indicating a CAN communication system ma ...

    Other materials:

    Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual > Theft Deterrent System: Terminals Of Ecu
    TERMINALS OF ECU CHECK MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) AND INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY (a) Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly. Click here (b) Reconnect the instrument panel junction block assembly conne ...

    Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual > Meter / Gauge System: Speed Signal Circuit
    DESCRIPTION The combination meter assembly receives the vehicle speed signal from this circuit. The wheel speed sensors produce an output that varies according to the vehicle speed. The wheel speed sensor output is received by the brake actuator assembly (skid control ECU) which uses this informatio ...

    Lexus RX (RX 350L, RX450h) 2016-{YEAR} Owners Manual

    Lexus RX (RX 350L, RX450h) 2016-{YEAR} Repair Manual

    © 2026 Copyright www.lexusrx.net
    0.0103