Toyota Tacoma (2015-2018) Service Manual: Open / Short in Steering Lock ECU (B2781)

Toyota Tacoma (2015-2018) Service Manual / Steering Column / Steering Lock System / Open / Short in Steering Lock ECU (B2781)

DESCRIPTION

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

The steering lock ECU (steering lock actuator or UPR bracket assembly) detects whether the steering lock is in the lock or unlock position by using the lock sensor and unlock sensor of the steering lock motor.

The steering lock ECU (steering lock actuator or UPR bracket assembly) 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 (steering lock actuator or UPR bracket assembly) is not connected to the CAN communication system. However, the steering lock ECU (steering lock actuator or UPR bracket assembly) 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 Item	DTC Detection Condition	Trouble Area	Note
B2781	Open / Short in Steering Lock ECU	One of the following conditions is met (1-trip detection logic1) : The steering lock sensor or unlock sensor is malfunctioning2. 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 or UPR bracket assembly) LIN communication system	DTC Output Confirmation Operation: No confirmation operation is necessary (monitoring is continuous).

*1: Only output while a malfunction is present and the engine switch is on (IG).
*2: When both detection switches turn on, the system is determined to be malfunctioning.

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 No.	Data List Item	Active Test Item
B2781	Smart Key Sensor Value Motor Driver Short	-

CAUTION / NOTICE / HINT

NOTICE:

When using the Techstream with the engine 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 Key. 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.
After performing repairs, confirm that no DTCs are output again (See page ).
When replacing the steering lock ECU (steering lock actuator or UPR bracket assembly), registration must be performed (See page ).

HINT:

When all the ECUs that are connected via LIN communication cannot communicate with the certification ECU (smart key ECU assembly), DTC B2785 is stored.

PROCEDURE

CHECK DTC

(a) Using the Techstream, check if LIN communication DTC B2785 is output (See page HINT: ).

HINT:

If a LIN communication DTC is output, perform troubleshooting for the LIN communication system (See page Result ).

Result

Result	Proceed to
DTC B2785 is output.	A
DTC B2785 is not output.	B

GO TO LIN COMMUNICATION SYSTEM (DTC B2785)

REPLACE STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPR BRACKET ASSEMBLY)

Diagnostic Trouble Code Chart

DIAGNOSTIC TROUBLE CODE CHART Steering Lock System DTC Code Detection Item See page B2781 Open / Short in Steering Lock ECU ...

Power Source Control ECU Malfunction (B2782)

DESCRIPTION DESCRIPTION The certification ECU (smart key ECU assembly) has a power source mode switching function. This DTC is stored when the IGE input (the steering lock motor activation permiss ...

Other materials:

Installation
INSTALLATION CAUTION / NOTICE / HINT HINT: Use the same procedure for both the LH and RH sides. The procedure described below is for the LH side. PROCEDURE 1. INSTALL HEADLIGHT ASSEMBLY (a) Connect the connectors. (b) Engage the clamp to install the headlight assembly. (c) ...

Operation Check
OPERATION CHECK 1. OPERATION DESCRIPTION (a) Push-button start function: (1) When the electrical key transmitter sub-assembly is in a detection area inside the vehicle and the brake pedal is depressed, the engine is started by pressing the engine switch. (2) When the electrical key transmitt ...

Key-off Operation Function Operates even if Operating Conditions are not Satisfied
DESCRIPTION When the front doors are closed, each power window regulator motor assembly can control its power window operation for approximately 43 seconds after the ignition switch is turned from ON to off by receiving operation permission signals from the main body ECU. How ...