Lexus RX (RX 350L, RX450h) 2016-2024 Repair Manual: Power Source Control ECU Malfunction (B2782)

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 upper bracket assembly) is determined to be abnormal.

HINT:

The steering lock ECU (steering lock actuator or upper bracket assembly) is not connected to the CAN communication system. However, the steering lock ECU (steering lock actuator or upper 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 (Only output while a malfunction is present and the engine switch is on (IG).)): 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 upper 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.)

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 B2782

DTC No.	Data List Item	Active Test Item
B2782	-	-

WIRING DIAGRAM

CAUTION / NOTICE / HINT

PROCEDURE

1.	INSPECT STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY)

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

(b) Disconnect the L1 steering lock ECU (steering lock actuator or upper bracket assembly) connector.

(c) Measure the resistance according to the value(s) in the table below. Standard Resistance: Tester Connection Condition Specified Condition L1-1 (GND) - Body ground Always Below 1 Ω

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

(d) Reconnect the L1 steering lock ECU (steering lock actuator or upper 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 L1-3 (IGE) - L1-1 (GND) Tool Setting 2 V/DIV., 200 ms./DIV. Vehicle Condition Steering lock motor not operating → Operating → Not 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.

*a Component with harness connected (Steering Lock ECU (Steering Lock Actuator or Upper Bracket Assembly)) *b Steering Lock Motor not Operating *c Steering Lock Motor Operating

NG

GO TO STEP 4

OK

2.	CLEAR DTC AND DATA LIST MALFUNCTION RECORD

(a) Clear the DTCs.

Click here

Body Electrical > Smart Access > Clear DTCs

(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.

Click here

NEXT

3.

CHECK DTC

(a) Perform the DTC output confirmation operation.

(b) Check if DTC B2782 is output.

Click here

Body Electrical > Smart Access > Trouble Codes

Result	Proceed to
DTC B2782 is not output.	A
DTC B2782 is output.	B

A

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

B

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

4.	CHECK HARNESS AND CONNECTOR (STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER 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 L1 steering lock ECU (steering lock actuator or upper bracket assembly) connector.

(c) Disconnect the J41 certification ECU (smart key ECU 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
L1-3 (IGE) - J41-25 (SLR+)	Always	Below 1 Ω
L1-3 (IGE) or J41-25 (SLR+) - Body ground	Always	10 kΩ or higher

OK

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR