Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Engine Circuit Malfunction (C1280)

Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual / Drivetrain / Mf1a (transfer / 4wd / Awd) / Dynamic Torque Control Awd System / Engine Circuit Malfunction (C1280)

DESCRIPTION

If a malfunction in the ECM circuit is detected, the 4WD ECU assembly stores this DTC.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

C1280

Engine Circuit Malfunction

When the following continues for 5 seconds or more:

  • Communication with engine control ECM is operating normally, but engine control system is malfunctioning.
  • Engine control 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

HINT:

Check the condition of each related circuit connector before troubleshooting.

Click here

PROCEDURE

1.

CHECK FOR DTC (SFI SYSTEM)

(a) Check if SFI system DTCs are output.

Click here

Powertrain > Engine > Trouble Codes

Result

Proceed to

SFI system DTCs are not output

A

SFI system DTCs are output

B
A

REPLACE 4WD ECU ASSEMBLY

B

GO TO SFI SYSTEM (DIAGNOSTIC TROUBLE CODE CHART)

    Low or High Power Supply Voltage (C1241)
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    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 DT ...

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