Toyota Avalon (XX50) 2019-2022 Service & Repair Manual: Unable to Unlock Steering Wheel (Engine cannot Start)

DESCRIPTION

The steering lock actuator or upper bracket assembly activates the steering lock motor and moves the lock bar into the steering column to lock the steering.

The steering may not unlock when the lock bar gets stuck in the lock hole of the steering column. In this case, if the engine switch is turned on (IG) while shaking the steering wheel, as is done for a vehicle with a mechanical key, the lock bar will be unlocked. If the certification ECU (smart key ECU assembly) or ECM is replaced, the system needs to be initialized. Otherwise, the steering cannot be unlocked and the engine cannot be started.

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 Model Code "KEY REGIST" 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.
• Perform either of the following operations to lock/unlock the steering:
  • 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.
• The smart key system (for Start Function, Gasoline Model) uses the LIN communication system and CAN communication system. Inspect the communication function by following How to Proceed with Troubleshooting. Troubleshoot the smart key system (for Start Function, Gasoline Model) after confirming that the communication systems are functioning properly.

  Click here

• After performing repairs, confirm that the problem does not recur.
• Make sure that no DTCs are output. If any DTCs are output, proceed to the Diagnostic Trouble Code Chart.

  Click here

• Inspect the fuses for circuits related to this system before performing the following procedure.
• Before replacing the steering lock ECU (steering lock actuator or upper bracket assembly) or certification ECU (smart key ECU assembly), refer to Registration.

  Click here

• When disconnecting the cable from the negative (-) battery terminal, some systems need to be initialized after the cable is reconnected.

  Click here

• If the steering lock ECU (steering lock actuator or upper bracket assembly) is replaced, be sure to confirm that the steering is unlocked by turning the steering wheel to the left and right before starting the engine. This function prevents the engine from starting while the steering is locked. If the steering is locked for any reason, open and close a door with the engine switch off, and then unlock the steering by pressing the engine switch.

PROCEDURE

(a) Check the power source mode change.

(1) When the key is inside the vehicle and the shift lever is in P, check that pressing the engine switch with the brake pedal released causes the power source mode to change as follows:

OK:

Off → On (ACC) → On (IG) → Off

NG

GO TO OTHER PROBLEM

OK

(a) With the engine switch on (IG), check that Steering Lock active is displayed on the multi-information display in the combination meter assembly.

B

GO TO STEP 4

A

(a) Turn the steering wheel left and right, and then press the engine switch.

(b) Check that the steering is unlocked.

A

USE SIMULATION METHOD TO CHECK

B

(a) Using the Techstream, check if the certification ECU (smart key ECU assembly) DTC is output.

B

GO TO DIAGNOSTIC PROCEDURE INDICATED BY OUTPUT DTC

A

(a) Use the Data List to check if the steering lock request is functioning properly.

OK:

Within 10 seconds of turning the engine switch on (ACC) or on (IG) or starting the engine, the Data List item changes to "OK".

NG

GO TO STEP 11

OK

(a) Use the Data List to check if L code certification is functioning properly.

OK:

OK is displayed on the Techstream.

HINT:

Reasons for verification failure:

• The steering lock ECU (steering lock actuator or upper bracket assembly) or certification ECU (smart key ECU assembly) is malfunctioning.
• There is a problem with the communication between ECUs.
• An ECU is replaced, but is not registered.
• An ECU is replaced with an ECU which has a code already stored in it.

NG

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

OK

(a) Measure the resistance and voltage according to the value(s) in the table below. Standard Resistance: Tester Connection Condition Specified Condition G43-1 (GND) - Body ground Always Below 1 Ω NOTICE: If the result is not as specified, check for looseness in the ground cable connection. Standard Voltage: Tester Connection Condition Specified Condition G43-7 (B) - Body ground Always 11 to 14 V

*a Component with harness connected (Steering Lock ECU (Steering Lock Actuator or Upper Bracket Assembly))

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

(a) Connect the G43 steering lock ECU (steering lock actuator or upper bracket assembly) connector.

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

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

OK:

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 electrical key transmitter sub-assembly 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.

OK

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

NG

(a) Disconnect the G43 steering lock ECU (steering lock actuator or upper bracket assembly) connector.

(b) Disconnect the G40 certification ECU (smart key ECU assembly) connector.

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

Standard Resistance:

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

(a) Connect the G43 steering lock ECU (steering lock actuator or upper bracket assembly) connector.

(b) Connect the G40 certification ECU (smart key ECU assembly) connector.

(c) Measure the voltage according to the value(s) in the table below. Standard Voltage: Tester Connection Condition Specified Condition G43-3 (IGE) - Body ground Always 11 to 14 V

*a Component with harness connected (Steering Lock ECU (Steering Lock Actuator or Upper Bracket Assembly))

OK

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

NG

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

(a) Measure the voltage according to the value(s) in the table below. Standard Voltage: Tester Connection Condition Specified Condition G43-4 (SLP1) - Body ground Always 11 to 14 V

*a Component with harness connected (Steering Lock ECU (Steering Lock Actuator or Upper Bracket Assembly))

NG

GO TO STEP 13

OK

(a) Check that the steering is locked.

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

OK:

Set is displayed on the Techstream.

OK

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

NG

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

(a) Disconnect the G43 steering lock ECU (steering lock actuator or upper bracket assembly) connector.

(b) Disconnect the G40 certification ECU (smart key ECU assembly) connector.

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

Standard Resistance:

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

(a) Replace the steering lock ECU (steering lock actuator or upper bracket assembly) with a new one.

for Manual Tilt and Manual Telescopic Steering Column: Click here

for Power Tilt and Power Telescopic Steering Column: Click here

(b) Perform registration.

Click here

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

(d) Use the Data List to check if the steering lock request is functioning properly.

OK:

Within 10 seconds of turning the engine switch on (ACC) or on (IG) or starting the engine, the Data List item changes to "OK".

OK

END (STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY) WAS DEFECTIVE)

NG

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)