Toyota Tacoma manuals

Toyota Tacoma (2015-2018) Service Manual: Unable to Lock Steering Wheel

Toyota Tacoma (2015-2018) Service Manual / Steering Column / Steering Lock System / Unable to Lock Steering Wheel

DESCRIPTION

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

When the steering lock is operating, the steering may not lock when the lock bar is not aligned with the lock hole of the steering column. In this case, the steering can be locked by turning the steering wheel a little, as is done for a vehicle with a mechanical key, to change the position of the lock hole.

Related Data List and Active Test Items

Problem Symptom

Data List Item

Active Test Item

Steering Lock does not Lock

Smart Key

  • Lock Request Receive
  • L Code Check
  • Steering Lock

Main Body

  • FL Door Courtesy SW

Power Source Control

  • Shift P Signal

-

WIRING DIAGRAM

CAUTION / NOTICE / HINT

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.
  • 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.
  • Make sure that no DTCs are output. If any DTCs are output, proceed to the Diagnostic Trouble Code Chart (See page The steering lock system uses LIN communication. First perform the inspections ).
  • 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 replacing the steering lock ECU (steering lock actuator or UPR ).
  • 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 After performing repairs, confirm that the problem does not recur. ).
  • After performing repairs, confirm that the problem does not recur.
  • Inspect the fuses for circuits related to this system before performing the following procedure.
  • When disconnecting the cable from the negative (-) battery terminal, some systems need to be initialized after the cable is reconnected (See page ).

PROCEDURE

1.

READ VALUE USING TECHSTREAM (LOCK REQUEST RECEIVE)

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

Smart Key

Tester Display

Measurement Item/Range

Normal Condition

Diagnostic Note

Lock Request Receive

Reception state of steering lock request signal by certification ECU (smart key ECU assembly) /

OK or NG

HINT:

  • The reception state is maintained for 10 seconds.
  • When 10 seconds or more elapsed after receiving the signal, the item changes to "NG".

OK: Within 10 seconds of opening any door with engine switch off and shift lever in P

NG: Except above

If this item does not change to "OK" even though the steering lock conditions are met, the certification ECU (smart key ECU assembly) may be malfunctioning.

OK:

The certification ECU (smart key ECU assembly) receives a lock request signal within 10 seconds of turning the engine switch from on (IG) to on (ACC) or off and opening a door with the shift lever in P, and OK is displayed on the Techstream screen.

NG

GO TO STEP 8

OK

2.

READ VALUE USING TECHSTREAM (L CODE CHECK)

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

Smart Key

Tester Display

Measurement Item/Range

Normal Condition

Diagnostic Note

L Code Check

Verification result between certification ECU (smart key ECU assembly) and steering lock ECU (steering lock actuator or UPR bracket assembly) /

OK or NG

OK: Verification result normal

NG: Verification result abnormal

When a malfunction is present:

  • The ID code for the certification ECU (smart key ECU assembly) or steering lock ECU (steering lock actuator or UPR bracket assembly) is not registered or the certification ECU (smart key ECU assembly) or steering lock ECU (steering lock actuator or UPR bracket assembly) is malfunctioning.
  • The steering cannot be locked.
  • The steering cannot be unlocked (the engine cannot be started).

OK:

OK is displayed on the Techstream.

HINT:

Reasons for verification failure:

  • The steering lock ECU (steering lock actuator or UPR 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

GO TO STEP 7

OK

3.

CHECK HARNESS AND CONNECTOR (POWER SOURCE TERMINAL)

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

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

S45-1 (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

S45-7 (B) - Body ground

Always

11 to 14 V
Text in Illustration

*a

Front view of wire harness connector

(to Steering Lock ECU (steering lock actuator or UPR bracket assembly))
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

4.

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

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

(b) 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

*a

Component with harness connected

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

*b

Steering Lock Motor not Operating

*c

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.
OK

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

NG

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

(c) Disconnect the C29 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

S45-3 (IGE) - C29-24 (SLR+)

Always

Below 1 Ω

S45-3 (IGE) or C29-24 (SLR+) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

6.

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

(a) Reconnect the S45 steering lock ECU (steering lock actuator or UPR bracket assembly) connector.

(b) Reconnect the C29 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

S45-3 (IGE) - Body ground

Always

11 to 14 V
Text in Illustration

*a

Component with harness connected

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

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

NG

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

7.

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

(a) Replace the steering lock ECU (steering lock actuator or UPR bracket assembly) with a new one (See page (b) Perform registration (See page ). ).

(b) Perform registration (See page (c) Use the Data List to check if L code certification is functioning properly. ).

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

Smart Key

Tester Display

Measurement Item/Range

Normal Condition

Diagnostic Note

L Code Check

Verification result between certification ECU (smart key ECU assembly) and steering lock ECU (steering lock actuator or UPR bracket assembly) /

OK or NG

OK: Verification result normal

NG: Verification result abnormal

When a malfunction is present:

  • The ID code for the certification ECU (smart key ECU assembly) or steering lock ECU (steering lock actuator or UPR bracket assembly) is not registered or the certification ECU (smart key ECU assembly) or steering lock ECU (steering lock actuator or UPR bracket assembly) is malfunctioning.
  • The steering cannot be locked.
  • The steering cannot be unlocked (the engine cannot be started).

OK:

OK is displayed on the Techstream.

OK

END
NG

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

8.

READ VALUE USING TECHSTREAM (DOOR COURTESY SW)

(a) Using the Techstream, check the following main body ECU (multiplex network body ECU) Data List item by opening and closing the driver door to confirm the state of the front door courtesy light switch assembly.

Main Body

Tester Display

Measurement Item/Range

Normal Condition

Diagnostic Note

FL Door Courtesy SW

Front door courtesy light switch assembly LH /

ON or OFF

ON: Front door LH open

OFF: Front door LH closed

If this item does not change according to the actual state of the driver door, there is a malfunction in the door courtesy light switch or related part.

OK:

The Data List item changes in accordance with the opening and closing of the driver door.

NG

GO TO LIGHTING SYSTEM (FRONT DOOR COURTESY SWITCH CIRCUIT)

OK

9.

READ VALUE USING TECHSTREAM (SHIFT P SIGNAL)

(a) Move the shift lever to P.

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

Power Source Control

Tester Display

Measurement Item/Range

Normal Condition

Diagnostic Note

Shift P Signal

Shift position (P) signal /

ON or OFF

ON: Shift lever in P

OFF: Shift lever not in P
  • Use this item to determine if the shift position switch is malfunctioning.
  • The engine cannot be started when this item is "OFF".

OK:

ON is displayed on the Techstream.

NG

GO TO ENTRY AND START SYSTEM (for Start Function) (PROBLEM SYMPTOMS TABLE)

OK

10.

READ VALUE USING TECHSTREAM (STEERING LOCK)

(a) Check that the steering is unlocked.

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

Smart Key

Tester Display

Measurement Item/Range

Normal Condition

Diagnostic Note

Steering Lock

State of whether steering lock ECU (steering lock actuator or UPR bracket assembly) determined steering is locked /

Set or Unset

Set: Steering locked

Unset: Steering unlocked

If this item displays "Unset", the steering is not locked.

OK:

Set is displayed on the Techstream.

NG

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

OK

11.

READ VALUE USING TECHSTREAM (LOCK REQUEST RECEIVE)

(a) Replace the certification ECU (smart key ECU assembly) with a new one.

(b) Perform registration (See page (c) Turn the engine switch on (IG). ).

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

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

Smart Key

Tester Display

Measurement Item/Range

Normal Condition

Diagnostic Note

Lock Request Receive

Reception state of steering lock request signal by certification ECU (smart key ECU assembly) /

OK or NG

HINT:

  • The reception state is maintained for 10 seconds.
  • When 10 seconds or more have elapsed after receiving the signal, the item changes to "NG".

OK: Lock request received within 10 seconds of opening any door with engine switch off and shift lever in P

NG: Except above

If this item does not change to "OK" even though the steering lock conditions are met, the certification ECU (smart key ECU assembly) may be malfunctioning.

OK:

The certification ECU (smart key ECU assembly) receives a lock request signal within 10 seconds of turning the engine switch from on (IG) to on (ACC) or off and opening a door with the shift lever in P, and OK is displayed on the Techstream screen.

OK

END
NG

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

IG2 Signal Malfunction (B2788)
DESCRIPTION This DTC is stored when the steering lock ECU (steering lock actuator or UPR bracket assembly) detects an IG2 power supply malfunction. HINT: The steering lock ECU (steering lock actu ...

Unable to Unlock Steering Wheel (Engine cannot Start)
DESCRIPTION The steering lock actuator 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 ba ...

Other materials:

Illumination Circuit
DESCRIPTION Power is supplied to the radio and display receiver assembly and steering pad switch assembly illumination when the light control switch is in the TAIL or HEAD position. WIRING DIAGRAM CAUTION / NOTICE / HINT NOTICE: The vehicle is equipped with a Supplemental Restrain ...

Multi-terrain Select Indicator Light Remains ON
DESCRIPTION Refer to Multi-terrain Select Indicator Light does not Come ON (See page ). WIRING DIAGRAM CAUTION / NOTICE / HINT NOTICE: When replacing the skid control ECU (master cylinder solenoid), perform calibration (See page ). Inspect the fuses for circuits related ...

On-vehicle Inspection
ON-VEHICLE INSPECTION PROCEDURE 1. INSPECT CAMSHAFT TIMING GEAR BOLT (a) Remove the camshaft timing oil control solenoid assembly (See page ). (b) Check that the plunger strokes when the plunger in the center of the camshaft timing gear bolt is pressed. Standard stroke: 4 ...

© 2011-2025 Copyright www.ttguide.net