Toyota 4Runner: IG2 Signal Malfunction (B2788)

Toyota 4Runner Service Manual / Steering / Steering Column / Steering Lock System / IG2 Signal Malfunction (B2788)

DESCRIPTION

The steering lock ECU determines the on/off status of the engine switch through the IG2 signal circuit.

The steering lock ECU does not lock the steering when it receives the IG2 relay on signal. This prevents the steering from being locked while the vehicle is moving.

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
B2788	The IG2 input to the steering lock ECU does not match the LIN communication input.	IGN fuse Steering lock actuator assembly (steering lock ECU) Power management control ECU Harness or connector

WIRING DIAGRAM

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 ).

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE

1.	CHECK STEERING LOCK ACTUATOR ASSEMBLY (STEERING LOCK ECU)

(a) Disconnect the F68 steering lock ECU connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection	Condition	Specified Condition
F68-1 (GND) - Body ground	Always	Below 1 Ω

Text in Illustration

*a	Front view of wire harness connector (to Steering Lock ECU)

(d) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
F68-6 (IG2) - F68-1 (GND)	Engine switch on (IG)	11 to 14 V
F68-6 (IG2) - F68-1 (GND)	Engine switch off	Below 1 V

Text in Illustration

*a	Component with harness connected (Steering Lock ECU)

REPLACE STEERING LOCK ACTUATOR ASSEMBLY (STEERING LOCK ECU)

CHECK FOR SHORT IN ALL HARNESSES, CONNECTORS AND COMPONENTS CONNECTED TO IG2 FUSE

Diagnostic Trouble Code Chart

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Power Source Control ECU Malfunction (B2782)

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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