Lexus NX manuals

Lexus NX: Power Source Control ECU Malfunction (B2782)

Lexus NX Service Manual / Steering / Steering Column / Steering Lock System / 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 assembly) is determined to be abnormal.

HINT:

The steering lock ECU (steering lock actuator assembly) is not connected to the CAN communication system. However, the steering lock ECU (steering lock actuator 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 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 power switch off. The steering unlocks when the power switch is turned on (ACC) or on (IG) while carrying the key.)
  • *: Only output while a malfunction is present and the power 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 hybrid control system cannot be started.

Prohibits the hybrid control system from being started (the hybrid control system does not crank).
Related Data List and Active Test Items

DTC No.

Data List Item

Active Test Item

B2782
Smart Access
  • Power Supply Short

-

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • When using the Techstream with the power 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.
  • 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.

    Click here

  • After performing repairs, perform the DTC output confirmation operation, and then confirm that no DTCs are output again.

    Click here

  • When replacing the steering lock ECU (steering lock actuator assembly) or certification ECU (smart key ECU assembly), registration must be performed.

    Click here

  • After the power switch is turned off, there may be a waiting time before disconnecting the negative (-) auxiliary battery terminal.

    Click here

  • When disconnecting and reconnecting the auxiliary battery

    Click here

    HINT:

    When disconnecting and reconnecting the auxiliary battery, there is an automatic learning function that completes learning when the respective system is used.

    Click here

PROCEDURE

1.

CHECK HARNESS AND CONNECTOR (GROUND)

(a) Disconnect the I2 steering lock ECU (steering lock actuator assembly) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

I2-1 (GND) - Body ground

Always

Below 1 Ω

*a

Front view of wire harness connector

(to Steering Lock ECU (Steering Lock Actuator Assembly))
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

2.

INSPECT STEERING LOCK ECU (STEERING LOCK ACTUATOR ASSEMBLY) (MOTOR ACTIVATION COMMAND SIGNAL)

(a) Reconnect the I2 steering lock ECU (steering lock actuator assembly) connector.

(b) Move the shift lever to P and turn the power switch off.

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

Standard Frequency:

Item

Content

Tester Connection

I2-3 (IGE) - I2-1 (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 power switch on (ACC) or on (IG).
    • To lock the steering, turn the power switch off with the shift lever in P, and then open a door.

*a

Component with harness connected

(Steering Lock ECU (Steering Lock Actuator Assembly))

*b

Steering Lock Motor not Operating

*c

Steering Lock Motor Operating
NG

GO TO STEP 5

OK

3.

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

NOTICE:

  • After the power switch is turned off, there may be a waiting time before disconnecting the negative (-) auxiliary battery terminal.

    Click here

  • When disconnecting and reconnecting the auxiliary battery

    Click here

    HINT:

    When disconnecting and reconnecting the auxiliary battery, there is an automatic learning function that completes learning when the respective system is used.

    Click here

NEXT

4.

READ VALUE USING TECHSTREAM (POWER SUPPLY SHORT)

(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 (for Manual tilt and manual telescopic steering column).

B

DTC B2782 is output (for Power tilt and power telescopic steering column).

C
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 ASSEMBLY)

C

REPLACE STEERING LOCK ECU (STEERING LOCK ACTUATOR ASSEMBLY)

5.

CHECK HARNESS AND CONNECTOR (STEERING LOCK ECU (STEERING LOCK ACTUATOR 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 I2 steering lock ECU (steering lock actuator assembly) connector.

(c) Disconnect the I53 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

I2-3 (IGE) - I53-24 (SLR+)

Always

Below 1 Ω

I2-3 (IGE) - Body ground

Always

10 kΩ or higher

I53-24 (SLR+) - Body ground

Always

10 kΩ or higher
OK

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

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