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DTC B2781: Open / Short in Steering Lock ECU [09/2014 - 01/2023]: Description

The steering lock ECU and steering lock motor are built into the steering lock actuator assembly.

The steering lock ECU (steering lock actuator assembly) detects whether the steering lock is in the lock or unlock position by using the lock sensor and unlock sensor of the steering lock motor.

The steering lock ECU (steering lock actuator assembly) receives lock and unlock request signals from the certification ECU (smart key ECU assembly) and responds with lock and unlock operation signals.

HINT: 

The steering lock ECU (steering lock actuator assembly) is not connected to the CAN communication system. However, the steering lock ECU (steering lock actuator assembly) is connected to the certification ECU (smart key ECU assembly) via LIN communication and communicates with other components via CAN communication through the certification ECU (smart key ECU assembly).

DTC No. Detection Item DTC Detection Condition Trouble Area Note
B2781 Open / Short in Steering Lock ECU One of the following conditions is met (1-trip detection logic (Only output while a malfunction is present and the engine switch is on (IG).)):
  • The steering lock sensor or unlock sensor is malfunctioning (When both detection switches turn on, the system is determined to be malfunctioning).
  • The steering lock motor activation circuit has a short circuit.
  • The steering lock motor activation circuit has an open circuit.
  • Steering lock ECU (Steering lock actuator assembly)
  • LIN communication system
DTC Output Confirmation Operation: No confirmation operation is necessary (monitoring is continuous).
Fig 1: Steering Lock/Unlock Sensor Diagram
GTY514357Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
VEHICLE CONDITION AND FAIL-SAFE FUNCTION WHEN MALFUNCTION DETECTED

Vehicle Condition when Malfunction Detected Fail-safe Function when Malfunction Detected
The steering cannot be locked or unlocked. For this reason, the engine cannot be started. Prohibits the engine from being started (the engine does not crank).
RELATED DATA LIST AND ACTIVE TEST ITEMS

DTC No. Data List Item Active Test Item
B2781 Smart Access 
  • Sensor Value
  • Motor Driver Short
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