Toyota Tacoma (2015-2018) Service Manual: Power Source Control ECU Malfunction (B2782)

Toyota Tacoma (2015-2018) Service Manual / Steering Column / Steering Lock System / 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 permission signal) sent directly from the certification ECU (smart key ECU assembly) to the steering lock ECU (steering lock actuator or UPR bracket assembly) is determined to be abnormal.

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
B2782	Power Source Control ECU Malfunction	Either of the following conditions 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 or UPR bracket assembly) Certification ECU (Smart key ECU assembly) Harness or connector	DTC Output Confirmation Operation: Perform a steering lock/ unlock operation. (The steering locks when a door is opened with the shift lever in P and the engine switch off. The steering unlocks when the engine switch is turned on (ACC) or on (IG) while carrying the key.)

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Note

B2782

Power Source Control ECU Malfunction

Either of the following conditions 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 or UPR bracket assembly)
Certification ECU (Smart key ECU assembly)
Harness or connector

DTC Output Confirmation Operation: Perform a steering lock/ unlock operation. (The steering locks when a door is opened with the shift lever in P and the engine switch off. The steering unlocks when the engine switch is turned on (ACC) or on (IG) while carrying the key.)

*: Only output while a malfunction is present and the engine switch is on (IG).

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
B2782	Smart Key Power Supply Short	-

WIRING DIAGRAM

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.
The steering lock system uses LIN communication. First perform the inspections in "How to Proceed with Troubleshooting" to confirm that there are no communication malfunctions before proceeding with troubleshooting (See page ).
When disconnecting the cable from the negative (-) battery terminal, some systems need to be initialized after the cable is reconnected (See page ).
After performing repairs, perform the DTC output confirmation operation, and then confirm that no DTCs are output again (See page ).
When replacing the steering lock ECU (steering lock actuator or UPR bracket assembly) or certification ECU (smart key ECU assembly), registration must be performed (See page ).

PROCEDURE

1.	INSPECT STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY (MOTOR ACTIVATION COMMAND SIGNAL)

(a) Make sure that there is no looseness at the locking part and the connecting part of the connector.

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

Standard Resistance:

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

Text in Illustration

*a	Front view of wire harness connector (to Steering Lock ECU (Steering Lock Actuator or UPR Bracket Assembly))

(d) Reconnect the steering lock ECU (steering lock actuator or UPR bracket assembly) connector.

(e) Move the shift lever to P and turn the engine switch off.

(f) Check the signal waveform according to the condition(s) in the table below.

Standard Frequency:

Item	Content
Tester Connection	S45-3 (IGE) - S45-1 (GND)
Tool Setting	2 V/DIV., 200 ms./DIV.
Vehicle Condition	Steering lock motor not operating → Operating → Not operating

Text in Illustration

Component with harness connected

(Steering Lock ECU (Steering Lock Actuator or UPR Bracket Assembly))

Steering Lock Motor not Operating

Steering Lock Motor Operating

HINT:

When taking measurements when the lock motor is stopped, it is not necessary to perform any operations.
In order to take measurements when the lock motor is operating, perform either of the following operations:
- To unlock the steering, carry the key and turn the engine switch on (ACC) or on (IG).
- To lock the steering, turn the engine switch off with the shift lever in P, and then open a door.

GO TO STEP 4

2.	CLEAR DTC AND DATA LIST MALFUNCTION RECORD

(a) Clear the DTCs (See page (b) Disconnect the cable from the negative (-) battery terminal, wait for 30 ).

(b) Disconnect the cable from the negative (-) battery terminal, wait for 30 seconds or more, and then reconnect the cable to the negative (-) battery terminal to clear the record of malfunctions stored in the Data List.

CAUTION:

After turning the engine switch off, waiting time may be required before disconnecting the cable from the battery terminal. Therefore, make sure to read the disconnecting the cable from the battery terminal notices before proceeding with work (See page ).

3.	READ VALUE USING TECHSTREAM (POWER SUPPLY SHORT)

(a) Perform the DTC output confirmation operation.

(b) Check if DTC B2782 is output (See page (c) Use the Data List to check if the steering lock control is functioning properly. ).

Smart Key

Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
Power Supply Short	Record of malfunction of signal sent to steering lock motor (steering lock actuator assembly) from certification ECU (smart key ECU assembly) (short circuit) (DTC B2782 is output) / OK or NG(Past)	OK: No record of malfunction (short circuit) NG(Past): Record of malfunction (short circuit) exists	This item records malfunctions in the circuit between the certification ECU (smart key ECU assembly) and steering lock motor (steering lock actuator assembly).

Tester Display

Measurement Item/Range

Normal Condition

Diagnostic Note

Power Supply Short

Record of malfunction of signal sent to steering lock motor (steering lock actuator assembly) from certification ECU (smart key ECU assembly) (short circuit) (DTC B2782 is output) /

OK or NG(Past)

OK: No record of malfunction (short circuit)

NG(Past): Record of malfunction (short circuit) exists

This item records malfunctions in the circuit between the certification ECU (smart key ECU assembly) and steering lock motor (steering lock actuator assembly).

Result

Result	Proceed to
DTC B2782 is not output. "OK" is displayed on the Techstream.	A
DTC B2782 is output. "OK" is displayed on the Techstream.	B

SYSTEM RETURNED TO NORMAL (DTC STORED DUE TO BAD CONNECTION, BUT SYSTEM RETURNED TO NORMAL BY RECONNECTING CONNECTOR)

REPLACE STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY

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

(a) Make sure that there is no looseness at the locking part and the connecting part of the connectors.

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

(d) Check for deformation and corrosion of the connector case and terminals.

OK:

There is no deformation or corrosion of the connector case or terminals.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
S45-3 (IGE) - C29-24 (SLR+)	Always	Below 1 Ω
S45-3 (IGE) or C29-24 (SLR+) - Body ground	Always	10 kΩ or higher

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

REPAIR OR REPLACE HARNESS OR CONNECTOR

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