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Home >> Subaru >> 2019 >> BRZ Limited, Automatic Trans >> Repair and Diagnosis >> Steering >> Steering Column >> Steering Lock System >> DTC B2781: Steering Lock ECU Open/Short >> Circuit description
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Circuit description

The steering lock ECM and steering lock motor are integrated into the steering lock actuator ASSY.

The steering lock actuator ASSY (Steering lock ECM) uses the steering lock motor lock position sensor to detect the lock/unlock position.

The steering lock actuator ASSY (Steering lock ECM) is input with a lock/unlock command signal from the smart key computer ASSY (Collation ECM) and returns a lock operation signal.

As the steering lock actuator ASSY (Steering lock ECM) is not connected to CAN communication, CAN communication with external parts is performed via the LIN communication-connected smart key computer ASSY (Collation ECM).

Diagnostic codes Detecting conditions Faulty part Diagnostic code output check operation
B2781 When one of the following conditions are satisfied (1 trip detection (1)).
  • Steering lock/unlock position detection sensor malfunction.(2)
  • Steering lock motor drive circuit short circuit malfunction.
  • Steering lock motor drive circuit open malfunction.
  • Steering lock actuator ASSY (Steering lock ECM)
  • Large-scale multiplex communication system for vehicle body [LIN]
No output verification required (constantly detected)
NOTE:
(1) Detects malfunctions when the vehicle is set to IG ON.

(2) Judged to be a malfunction when both detection switches are ON at the same time.
G12591259Courtesy of SUBARU OF AMERICA, INC.
VEHICLE STATE AND FAIL SAFE MEASURES DURING DETECTION

Vehicle state during detection Fail safe measures during detection
Steering lock, unlock cannot be performed. This means that the engine cannot be started. Engine starting is prohibited (Does not perform cranking).
RELATED DATA MONITOR AND ACTIVE TEST

Diagnostic codes Data monitor Active test
B2781 Check
  • Sensor malfunction history (Steering lock)
  • Motor driver short circuit history
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