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DTC B2781: Open / Short in Steering Lock ECU [03/2017 - ]: Description

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

The steering lock ECU detects whether the steering lock is in the lock or unlock position by using the lock position sensor of the steering lock motor.

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

HINT: 

The steering lock actuator assembly (steering lock ECU) is not connected to the CAN communication system. However, the steering lock actuator assembly (steering lock ECU) 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 Condition Trouble Area DTC Output Confirmation Operation
B2781 One of the following conditions is met (1-trip detection logic*1):
  • The steering lock/unlock position sensor is malfunctioning*2.
  • The steering lock motor activation circuit has a short circuit.
  • The steering lock motor activation circuit has an open circuit.
  • Steering lock actuator assembly (steering lock ECU)
  • LIN communication system
No confirmation operation is necessary (monitoring is continuous).
Fig 1: Unlock / Lock Sensor Diagram
GTY563412Courtesy 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 Data List Item Active Test Item
B2781 Smart Key 
  • Sensor Value
  • Power Supply Short
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