Unable to Unlock Steering Wheel (Engine cannot Start) [08/2013 - ]: Procedure

NG → REPAIR CIRCUITS INDICATED BY OUTPUT DTCS 

OK: Go to next step 

1. 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 → See step   13 

OK: Go to next step 

1. Use the Data List to check if the steering lock request is functioning properly.
   SMART ACCESS
   
   

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   Unlock Request Receive	Reception state of steering unlock request signal by certification ECU (smart key ECU assembly) and sent to ID code box (immobilizer code ECU) / 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: Within 10 seconds of turning engine switch on (IG) or on (ACC) or starting engine NG: Except above	If the unlock signal has not been received, the engine cannot be started. If this item does not change to "OK" even though the steering unlock conditions are met, the certification ECU (smart key ECU assembly) may be malfunctioning.

   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 → See step   6 

OK: Go to next step 

1. Disconnect the H18 steering lock ECU connector.
2. Measure the resistance and voltage according to the value(s) in the table below.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   H18-1 (GND) - Body ground	Always	Below 1 Ω

   NOTE:

   If the result is not as specified, check for looseness in the ground cable connection.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   H18-7 (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 Assembly))

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Reconnect the H18 steering lock ECU connector.
2. Check the signal waveform according to the condition(s) in the table below.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   STANDARD FREQUENCY
   
   

   Item	Content
   Tester Connection	H18-3 (IGE) - H18-1 (GND)
   Tool Setting	2 V/DIV., 200 ms./DIV.
   Vehicle Condition	Steering lock motor not operating → Steering lock motor operating → Steering lock motor not operating

   TEXT IN ILLUSTRATION
   
   

   *a	Component with harness connected (Steering Lock ECU (Steering Lock Actuator Assembly))
   *b	Steering lock motor not operating
   *c	Steering lock motor operating

   HINT: 

   • When taking measurements while 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) with the shift lever in P.
     • To lock the steering, turn the engine switch off with the shift lever in P, and then open a door.

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   11 

NG → See step   9 

OK: Go to next step 

NG → See step   10 

OK: Go to next step 

NG → See step   12 

OK → END 

NG → See step   14 

OK → END 

NG → See step   14 

OK → END