Toyota Tacoma (2015-2018) Service Manual: No Response from Steering Lock ECU (B2786)

Toyota Tacoma (2015-2018) Service Manual / Multiplex Communication / Lin Communication System / No Response from Steering Lock ECU (B2786)

DESCRIPTION

This DTC is stored when LIN communication between the certification ECU (smart key ECU assembly) and steering lock ECU (steering lock actuator or upper bracket assembly) stops for 10 seconds or more.

DTC No.	DTC Detection Condition	Trouble Area
B2786	No communication between steering lock ECU (steering lock actuator or upper bracket assembly) and certification ECU (smart key ECU assembly) for 10 seconds or more.	Steering lock ECU (steering lock actuator or upper bracket assembly) Certification ECU (smart key ECU assembly) Wire harness or connector

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following inspection procedure.
If the certification ECU (smart key ECU assembly) is replaced, register the keys (See page ).
If the steering lock ECU (steering lock actuator or upper bracket assembly) is replaced, register the ECU code (See page ).
When using the Techstream with the vehicle ignition switch off, connect the Techstream to the vehicle and turn a courtesy light switch on and off at intervals of 1.5 seconds or less until communication between the Techstream and the vehicle begins. Then select the vehicle type under manual mode and enter the following menus: Body Electrical / Smart Access. While using the Techstream, periodically turn a courtesy light switch on and off at intervals of 1.5 seconds or less to maintain communication between the Techstream and the vehicle.

PROCEDURE

1.	CHECK DTC OUTPUT

(a) Clear the DTCs (See page (b) Recheck for DTCs. ).

(b) Recheck for DTCs.

Result	Proceed to
Only B2786 is output	A
DTC B2786 and B2785 are output simultaneously	B

HINT:

When DTC B2786 and B2785 are output simultaneously, perform troubleshooting for DTC B2785 first.

GO TO DTC B2785

2.	CHECK HARNESS AND CONNECTOR (STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY) - POWER SOURCE CIRCUIT)

(a) Disconnect the S45 steering lock ECU (steering lock actuator or upper bracket assembly) connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
S45-1 (GND) - Body ground	Always	Below 1 Ω

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
S45-7 (B) - Body ground	Always	11 to 14 V
S45-6 (IG2) - Body ground	Ignition switch ON	11 to 14 V

REPAIR OR REPLACE HARNESS OR CONNECTOR

3.	CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY))

(a) Disconnect the C29 certification ECU (smart key ECU assembly) connector.

(b) Disconnect the S45 steering lock ECU (steering lock actuator or upper bracket assembly) connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
C29-6 (LIN) - S45-5 (LIN)	Always	Below 1 Ω
C29-6 (LIN) or S45-5 (LIN) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.	REPLACE STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY)

(a) Replace the steering lock ECU (steering lock actuator or upper bracket assembly) (See page ).

5.	CHECK DTC OUTPUT

(a) Clear the DTCs (See page (b) Recheck for DTCs. ).

(b) Recheck for DTCs.

OK:

DTC B2786 is not output.

END (STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY) WAS DEFECTIVE)

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

Communication Malfunction between ECUs Connected by LIN (B2785)

DESCRIPTION The certification ECU (smart key ECU assembly) monitors communication between all the ECUs connected to the certification bus lines. When the certification ECU (smart key ECU assembly ...

Diagnostic Trouble Code Chart

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Other materials:

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Test Mode Procedure
TEST MODE PROCEDURE 1. TEST MODE PROCEDURE (for Using Techstream) HINT: If the ignition switch is turned from the ON to the ACC or LOCK position during test mode, DTCs related to the signal check function will be cleared. During test mode, the skid control ECU (master cylinder ...

Problem Symptoms Table
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