Electric Power Steering System - Diagnostics: Calibration

1. INITIALIZATION OF TORQUE SENSOR ZERO POINT CALIBRATION SIGNAL 
   NOTE: Under the following conditions, perform torque sensor zero point calibration after initializing the torque sensor zero point calibration signal in the ECU:  

   • The steering column assy (containing the torque sensor) has been replaced. 
   • The power steering ECU assy has been replaced. 
   • The steering wheel has been replaced. 
   • The steering gear assy has been replaced. 
   • There is a difference in steering effort between right and left. 
   1. Center the steering wheel and align the front wheels straight ahead.
   2. Connect the hand-held tester to the DLC3.
   3. Turn the power switch on (IG) and then initialize the torque sensor zero point calibration signal by following the tester screen.
      NOTE: Do not turn the steering wheel while initializing the zero point calibration signal. 
   4. Perform steering zero point calibration after turning the power switch off.
   NOTE: Zero point calibration cannot be carried out with the power switch on (IG) after initialization of the zero point calibration signal is completed. 
   Fig 1: Torque Sensor Zero Point Calibration Signal (1 Of 2)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   Fig 2: Torque Sensor Zero Point Calibration Signal (2 Of 2)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. TORQUE SENSOR ZERO POINT CALIBRATION 
   1. Center the steering wheel and align the front wheels straight ahead.
   2. Connect the hand-held tester to the DLC3.
   3. Turn the power switch on (IG) and then perform the zero point calibration by following the tester screen.
      NOTE:

      • The vehicle is stopped. 
      • Do not start the engine. Do not turn the power switch on (READY). 
      • Do not turn the steering wheel. 
      • The vehicle is on level ground. 
   4. Confirm that no DTCs are output after completing the operation.
      • When DTC C1515 is output, see DTC C1515 TORQUE SENSOR ZERO POINT ADJUSTMENT UNDONE  .
      • When DTC C1516 is output, see DTC C1516 TORQUE SENSOR ZERO POINT ADJUSTMENT INCOMPLETE  .
      • When DTC C1534 is output, see DTC C1531 ECU ABNORMAL, DTC C1532 ECU ABNORMAL, DTC C1533 ECU ABNORMAL, DTC C1534 ECU ABNORMAL  .

Fig 3: Torque Sensor Zero Point Calibration (1 Of 2)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 4: Torque Sensor Zero Point Calibration (2 Of 2)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002