Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Steering Lock Position Signal Circuit Malfunction (B2285)

Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual / Vehicle Interior / Theft Deterrent / Keyless Entry / Smart Access System With Push-button Start (for Start Function) / Steering Lock Position Signal Circuit Malfunction (B2285)

DESCRIPTION

This DTC is stored when the steering lock position signal sent by the steering lock ECU (steering lock actuator or upper bracket assembly) via direct line and the steering lock position signal sent via LIN communication do not match.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Note

B2285

Steering Lock Position Signal Circuit Malfunction

The steering lock position signal sent by the steering lock ECU (steering lock actuator or upper bracket assembly) via direct line and the steering lock position signal sent via LIN communication do not match. (1-trip detection logic*1)
  • AM2 fuse
  • Steering lock ECU (steering lock actuator or upper bracket assembly)
  • Certification ECU (smart key ECU assembly)
  • Wire harness or connector
  • DCM (telematics transceiver)*2
  • Disconnect the cable from the negative (-) battery terminal, wait 30 seconds and then reconnect the cable to the negative (-) battery terminal. Wait at least 40 seconds with the engine switch off (wait is the steering locked), then turn the engine switch on (IG) (steering unlocked) and wait at least 40 seconds.
  • *1: Only detected while a malfunction is present and the engine switch is on (IG).
  • *2: for Lexus Enform Remote Compatible Type
Vehicle Condition and Fail-safe Function when Malfunction Detected

Vehicle Condition when Malfunction Detected

Fail-safe Function when Malfunction Detected

The engine cannot be started.

The ECU does not send an engine start request.
Related Data List and Active Test Items

DTC No.

Data List and Active Test

B2285
Power Source Control
  • Steering Unlock Switch
Smart Access
  • Power Supply Short
  • Motor Driver Short
  • Lock Bar Stuck Error

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • When using the Techstream with the engine switch off, connect the Techstream to the DLC3 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 smart access system with push-button start (for Start Function) uses the LIN communication system and CAN communication system. Inspect the communication function by following How to Proceed with Troubleshooting. Troubleshoot the smart access system with push-button start (for Start Function) after confirming that the communication systems are functioning properly.

    Click here

  • Inspect the fuses of circuits related to this system before performing the following procedure.
  • Before replacing the certification ECU (smart key ECU assembly), steering lock ECU (steering lock actuator or upper bracket assembly) or DCM (telematics transceiver)*, refer to the smart access system with push-button start (for Start Function) Precaution.

    Click here

  • After repair, confirm that no DTCs are output by performing "DTC Output Confirmation Operation".
  • *: for LEXUS ENFORM Remote Compatible Type

HINT:

When the cable is disconnected and reconnected to the negative (-) battery terminal, the power source mode returns to the state it was in before the cable was disconnected.

PROCEDURE

1.

CHECK FOR DTC

(a) Check for DTCs.

Body Electrical > Smart Access > Trouble Codes

HINT:

  • If the steering cannot be unlocked, the engine switch cannot be turned on (IG) and the engine cannot be started.
  • If LIN communication is not available, the steering cannot be locked or unlocked.

OK:

LIN communication system DTC B2785 is not output simultaneously.

NG

GO TO DTC B2785

OK

2.

READ VALUE USING TECHSTREAM (STEERING UNLOCK SWITCH)

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Power Source Control / Data List.

(e) Read the Data List according to the display on the Techstream.

Body Electrical > Power Source Control > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Steering Unlock Switch

State of steering unlock sensor signal output from steering lock ECU (steering lock actuator or upper bracket assembly)

OFF or ON

OFF: Steering locked

ON: Steering unlocked
  • When the shift lever is in P and the engine switch is off, if any door is opened or closed, the steering is locked.
  • When the electrical key transmitter sub-assembly is in the cabin and the engine switch is turned on (ACC) or on (IG), the steering unlocks.
  • The engine cannot be started when the steering unlock signal is off.
Body Electrical > Power Source Control > Data List

Tester Display

Steering Unlock Switch

Result

Proceed to

Techstream display does not change

A

Techstream display changes

B
B

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

A

3.

CHECK HARNESS AND CONNECTOR (POWER SOURCE)

Click here

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR IN CIRCUIT CONNECTED TO POWER SOURCE
OK

4.

CHECK HARNESS AND CONNECTOR (GROUND)

Click here

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

5.

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

(a) Reconnect the J41 certification ECU (smart key ECU assembly) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

L1-4 (SLP1) - Body ground

Positive (+) tester probe → L1-4 (SLP1)

Negative (-) tester probe → Body ground

Steering locked → unlocked*

10 kΩ or higher → Below 1 Ω

HINT:

  • *: If any of the doors are opened with the shift lever in P and the engine switch off, the steering will be locked. If the engine switch is turned on (ACC) or on (IG) with the electrical key transmitter sub-assembly in the cabin, the steering will be unlocked.
  • DTC B2285 may be stored due to a malfunction in the steering lock ECU (steering lock actuator or upper bracket assembly). The steering lock position signal and unlock position signal are sent from the steering lock ECU (steering lock actuator or upper bracket assembly) to the certification ECU (smart key ECU assembly) individually.

*a

Component with harness connected

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

Result

Proceed to

OK (except Lexus Enform Remote Compatible Type)

A

OK (for Lexus Enform Remote Compatible Type)

B

NG

C
B

GO TO STEP 7

C

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

A

6.

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

(a) Disconnect the J41 certification ECU (smart key ECU assembly) 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

J41-14 (SLP) - L1-4 (SLP1)

Always

Below 1 Ω

J41-14 (SLP) or L1-4 (SLP1) - Body ground

Always

10 kΩ or higher
OK

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

7.

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

(a) Disconnect the J41 certification ECU (smart key ECU assembly) connector.

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

(c) Disconnect the J157 DCM (telematics transceiver) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

J41-14 (SLP) - L1-4 (SLP1)

Always

Below 1 Ω

L1-4 (SLP1) - J157-30 (SLPD)

Always

Below 1 Ω

J41-14 (SLP), L1-4 (SLP1) or J157-30 (SLPD) - Body ground

Always

10 kΩ or higher

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

J41-14 (SLP), L1-4 (SLP1) or J157-30 (SLPD) - Body ground

Steering locked

11 to 14 V

Steering unlocked

Below 1.5 V
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

8.

INSPECT CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

(a) Check the push-button start function.

(1) Enter the vehicle while carrying an electrical key transmitter sub-assembly.

(2) Depress the brake pedal with the shift lever in P.

(3) Check that the engine starts when the engine switch is pressed.

Result

Proceed to

Engine starts

A

Engine does not start

B
A

REPLACE DCM (TELEMATICS TRANSCEIVER)

B

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

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