Toyota 4Runner: Open / Short in Steering Lock ECU (B2781)

Toyota 4Runner Service Manual / Steering / Steering Column / Steering Lock System / Open / Short in Steering Lock ECU (B2781)

DESCRIPTION

The steering lock ECU and steering lock actuator assembly are supplied as a unit.

The steering lock ECU detects the steering lock position through the signals from the lock and unlock position sensors.

The steering lock ECU activates the steering lock motor based on permission signals from the power management control ECU and the certification ECU.

The diagnosis information of the steering lock ECU is transmitted to the Techstream via the certification ECU as the steering lock ECU is not connected to the CAN communication system.

DTC Code	Detection Condition	Trouble Area
B2781	Either condition is met: A steering lock motor drive power circuit malfunction. The lock and unlock position sensors are detected to be on.	Steering lock actuator assembly (steering lock ECU) LIN communication system Harness or connector of LIN bus line

CAUTION / NOTICE / HINT

HINT:

When the engine switch is off, the main body ECU may occasionally go into a non-active state called sleep mode. Therefore, before proceeding with the inspection, it is necessary to perform the following steps to wake up the ECU:

With the engine switch off, open the driver door. Then (with the engine switch still off) open and close any door several times at 1.5 second intervals.

NOTICE:

If the steering lock actuator assembly (steering lock ECU) is replaced, with the engine switch off and the shift lever in P, open and close the driver side door to record the current lock position into the steering lock ECU. If this is not performed, the engine may not start.
When replacing the steering lock ECU, registration must be performed (See page ).

PROCEDURE

1.	CHECK DTC OUTPUT (B2785)

(a) Check for DTCs (See page ).

Result

Result	Proceed to
DTC B2781 and DTC B2785 are output	A
DTC B2781 is output, but DTC B2785 is not output	B

GO TO LIN COMMUNICATION SYSTEM (DTC B2785)

REPLACE STEERING LOCK ACTUATOR ASSEMBLY (STEERING LOCK ECU)

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DESCRIPTION The steering lock ECU activates the steering lock motor with the power from the power management control ECU through the IGE circuit. This prevents the steering from being locked whil ...

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DESCRIPTION The steering lock ECU sends an unlock position signal to the power management control ECU. Upon receiving the signal, the power management control ECU permits an engine start. This pr ...

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