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Steering Lock System (Diagnostic Codes & Symptom Tests): Overview Lexus GS IV

Steering Column 5 illustrations ~613 words

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

HINT

The steering lock ECU is not connected to the CAN communication system. However, the 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 ConditionTrouble AreaDTC Output Confirmation Operation
B2781One 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 ECU (Steering lock actuator assembly) LIN communication systemNo confirmation operation is necessary (monitoring is continuous).
  1. *1: Only output while a malfunction is present and the power switch is on (IG).
  2. *2: When both detection switches turn on, the system is determined to be malfunctioning.

Scheme 61

Scheme 61
Vehicle Condition when Malfunction DetectedFail-safe Function when Malfunction Detected
The steering cannot be locked or unlocked. For this reason, the hybrid control system cannot be started.Prohibits the hybrid control system from being started.

VEHICLE CONDITION AND FAIL-SAFE FUNCTION WHEN MALFUNCTION DETECTED

DTC No.Data List ItemActive Test Item
B2781Smart Access Sensor Value Motor Driver Short

RELATED DATA LIST AND ACTIVE TEST ITEMS

The power management control ECU has a power source mode switching function.

This DTC is stored when the IGE input (the steering lock motor activation permission signal) sent directly from the power management control ECU to the steering lock ECU is determined to be abnormal.

HINT

The steering lock ECU is not connected to the CAN communication system. However, the 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 ConditionTrouble AreaDTC Output Confirmation Operation
B2782Either condition is met (1-trip detection logic*): The steering lock motor activation command circuit has a short circuit. The steering lock motor activation command circuit has an open circuit. HINT: If the power supply signal from the LIN communication line does not match the power supply signal from the direct line, the system is determined to be malfunctioning.Steering lock ECU (Steering lock actuator assembly) Power management control ECU Harness or connectorPerform a steering lock/unlock operation. (The steering locks when a door is opened with the shift lever in P and the power switch off. The steering unlocks when the power switch is turned on (ACC) or on (IG) while carrying the key.)
  1. *: Only output while a malfunction is present and the power switch is on (IG).
Vehicle Condition when Malfunction DetectedFail-safe Function when Malfunction Detected
The steering cannot be locked or unlocked. For this reason, the hybrid control system cannot be started.Prohibits the hybrid control system from being started.

VEHICLE CONDITION AND FAIL-SAFE FUNCTION WHEN MALFUNCTION DETECTED

DTC No.Data List ItemActive Test Item
B2782

RELATED DATA LIST AND ACTIVE TEST ITEMS

Scheme 62

Scheme 62: WIRING DIAGRAM

This DTC is stored when the steering lock ECU detects an IG2 power supply malfunction.

HINT

The steering lock ECU is not connected to the CAN communication system. However, the 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 ConditionTrouble AreaDTC Output Confirmation Operation
B2788Mismatch between the steering lock ECU IG2 input from the LIN communication system and from the direct line (1-trip detection logic*).LH-IG2 fuse Steering lock ECU (Steering lock actuator assembly) Harness or connectorNo confirmation operation is necessary (monitoring is continuous).
  1. *: Only output while a malfunction is present and the power switch is on (IG).
Vehicle Condition when Malfunction DetectedFail-safe Function when Malfunction Detected
The steering cannot be locked or unlocked. For this reason, the hybrid control system cannot be started.

VEHICLE CONDITION AND FAIL-SAFE FUNCTION WHEN MALFUNCTION DETECTED

DTC No.Data List ItemActive Test Item
B2788

RELATED DATA LIST AND ACTIVE TEST ITEMS

Scheme 63

Scheme 63: WIRING DIAGRAM

The steering lock actuator assembly activates the steering lock motor and moves the lock bar into the steering column to lock the steering.

The steering may not unlock when the lock bar gets stuck in the lock hole of the steering column. In this case, if a hybrid control system start operation is performed while shaking the steering wheel in the same manner as is done for a vehicle with a mechanical key, the lock bar will be unlocked. If the certification ECU (smart key ECU assembly), ID code box (immobilizer code ECU) or power management control ECU is replaced, the system needs to be initialized. Otherwise, the steering cannot be unlocked and the hybrid control system cannot be started.

Problem SymptomData List ItemActive Test Item
Unable to unlock steering wheel (Hybrid Control System cannot Start)Smart Access Unlock Request Receive S Code Check L Code Check

RELATED DATA LIST AND ACTIVE TEST ITEMS

Scheme 64

Scheme 64: WIRING DIAGRAM

The steering lock actuator activates the steering lock motor and moves the lock bar into the steering column to lock the steering.

When the steering lock is operating, the steering may not lock when the lock bar is not aligned with the lock hole of the steering column. In this case, the steering can be locked by turning the steering wheel a little in the same manner as is done for a vehicle with a mechanical key to change the position of the lock hole.

Problem SymptomData List ItemActive Test Item
Unable to lock steering wheelSmart Access Lock Request Receive S Code Check L Code Check Main Body FL Door Courtesy SW

RELATED DATA LIST AND ACTIVE TEST ITEMS

Scheme 65

Scheme 65: WIRING DIAGRAM