DTC C121A: Abnormality in steering wheel sensor initialization: Notes

CAUTION:

If there is any problem in the CAN bus lines, an incorrect diagnostic trouble code may be set. Prior to this diagnosis, diagnose the CAN bus lines (Refer to CAN BUS LINE DIAGNOSTIC FLOW .
Whenever ECU is replaced, ensure that the CAN bus lines are normal.
When the steering wheel sensor is replaced, always carry out calibration to make ASC-ECU learn the neutral point (Refer to STEERING WHEEL SENSOR CALIBRATION .
When the hydraulic unit (integrated with ASC-ECU) is replaced, always carry out the calibration of the steering wheel sensor, the G and yaw rate sensor and brake fluid pressure sensor (Refer to G AND YAW RATE SENSOR CALIBRATION , STEERING WHEEL SENSOR CALIBRATION and BRAKE FLUID PRESSURE SENSOR CALIBRATION .