Inspection Procedure

HINT:

This problem may be caused by a malfunction in the electronically controlled brake system or EPS system.

Make sure that no DTC is output for the skid control ECU, power steering ECU, or steering control ECU before proceeding with the following procedures.

If a DTC is output for any of these ECUs, first troubleshoot it and then proceed to the troubleshooting below.

1. READ VALUE OF INTELLIGENT TESTER 
   1. Connect the intelligent tester to the DLC3.
   2. Turn the power switch ON (IG) and intelligent tester on.
   3. Select the DATA LIST mode on the intelligent tester.

      Steering control ECU: 

      DATA LIST - STEERING CONTROL ECU
      
      

      Item	Measurement Item / Range (Display)	Normal Condition
      MTR OVERHEAT	Record of continuous overheat preventive control / Rec or Unrec	Rec or Unrec

      Result 

      RESULT REFERENCE
      
      

      Result	Proceed to
      "Rec" (Record motor overheating)	A
      "Unrec" (No record of motor overheating)	B

      HINT:

      If "Rec" is displayed, reset the setting to "Unrec". Enter the VGRS menu on the intelligent tester, select record clearance, and follow the prompts to set to "Unrec".

   B:  GO TO step  3

   A: GO TO Next Step 

2. CHECK HEAT PROTECTION FUNCTION FOR STEERING ACTUATOR 
   1. Turn the power switch ON (IG) and wait for 30 minutes until the steering actuator cools down.
   2. Start the engine and slowly turn the steering wheel from lock to lock (approximately 90°/sec) 3 times.

      HINT:

      If turning the steering wheel quickly while driving at low speeds, the steering angle may differ between left and right, or the steering wheel may become off-center. However, this is not a malfunction.

   3. Check the number of turns from lock to lock.

      Result 

      RESULT REFERENCE
      
      

      Result	Proceed to
      3.2 turns	A
      2.7 turns	B

   B: VGRS SYSTEM IS NORMAL 

   A: GO TO Next Step 

3. CHECK STEERING EFFORT 
   1. Start the engine.
   2. Turn the steering wheel.
   3. Check the steering effort.

      OK: 

      Below 6.5 N*m (66 kgf*cm, 57 in.*lbf) 

      HINT:

      After completing the inspection or repair, attempt to simulate the problem and then perform "READ VALUE OF INTELLIGENT TESTER" above again to reconfirm that the problem does not occur.

   NG:  GO TO POWER STEERING SYSTEM

   OK: GO TO Next Step 

4. CHECK STEERING ACTUATOR 
   1. Check for an abnormal noise or vibration in the steering actuator.

      OK: 

      Neither an abnormal noise or vibration occurs. 

   NG:  GO TO STEERING WHEEL VIBRATES OR ABNORMAL NOISE IS HEARD FROM STEERING WHEEL 

   OK: GO TO Next Step 

5. CHECK STEERING CONTROL ECU (POWER SOURCE CIRCUIT) 
   1. Turn the power switch ON (IG).
   2. Measure the voltage of the steering control ECU.

      Standard voltage 

      STANDARD VOLTAGE REFERENCE
      
      

      Tester Connection	Condition	Specified Condition
      A40-3 (IG) - Body ground	Power switch ON (IG)	10 to 14 V
      A40-8 (PIG) - Body ground	Power switch ON (IG)	10 to 14 V

      Fig 1: Checking Steering Control ECU (Power Source Circuit)

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   3. Turn the power switch OFF.
   4. Measure the resistance of the steering control ECU.

      Standard resistance 

      STANDARD RESISTANCE REFERENCE
      
      

      Tester Connection	Condition	Specified Condition
      A40-7 (PGND) -Body ground	Always	Below 1 Ω

   NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

   OK: REPLACE STEERING CONTROL ECU