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Fail-Safe Chart

If a problem occurs in the electronic power steering system, the P/S warning light will come on in the combination meter and steering power assistance will be stopped, fixed at a particular point, or decreased simultaneously to protect the system.

DTC No. Malfunction Fail-safe
C1511 Torque Sensor Circuit Malfunction Power assistance stops.
C1512
C1513
C1521 Motor Circuit Malfunction
C1522
C1523
C1524
C1528 Motor Rotation Angle Sensor Malfunction
C1531 ECU Malfunction
C1532
C1555 Motor Relay Welding Failure
C1533 ECU Malfunction System overheat prevention control continues without using the substrate temperature sensor.
C1534 ECU Malfunction Torque sensor zero point and rotation angle sensor calibration value are set to the default values.
C1541 Vehicle Speed Signal Malfunction Amount of power assistance is fixed for a speed of 100 km/h (62 mph).
U0121 Lost Communication With Anti-lock Brake System (ABS) Control Module

HINT: 

The amount of power assistance may be decreased to prevent the motor and ECUs from overheating if the steering wheel is continuously turned when the vehicle is either stopped or driven at a low speed, or if the steering wheel is kept at either full lock position for a long time. In that case, the amount of power assistance will return to normal if the steering wheel is not turned for approximately 10 minutes with the engine idling.