DTC Advanced Diagnostics: C1421-14
DTC C1421-14: Main Torque Sensor Malfunction
NOTE
Initial Diagnosis:
The initial on-board diagnosis occurs right after the vehicle condition is turned to the ON mode, and the EPS indicator comes on, and continues until the indicator goes off.
Regular Diagnosis:
The regular on-board diagnosis begins right after the EPS indicator goes off, and it continues until the vehicle condition is turned to the OFF (LOCK) mode.
Review "How to troubleshoot the EPS system" before doing the DTC troubleshooting procedure.
Test-drive the vehicle according to local traffic conditions and regulations. Do not test-drive on a lift unless specified.
The possible causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.

Confirmation Procedure
Basic Condition:
Torque sensor power supply voltage 4.5 - 5.5 V

With the Driving Pattern:
1.
Start the engine.
2.
Turn the steering wheel to left and right several times, and keep holding each direction for 10 seconds.
Execution
Regular Diagnosis
Duration
About 1 second
DTC Type
1 drive cycle
EPS indicator on
Fail Safe Action
Stop or continue EPS function/assist (Limited assist)
(Dependant upon the conditions)
Stop motion adaptive-EPS function/assist
Possible Cause
Open, Short to ground, Short to power, or Poor connection between the EPS motor/control unit and the torque sensor (TSM line)
Open between the EPS motor/control unit and the torque sensor (T/S VDD line)
Open between the EPS motor/control unit and the torque sensor (T/S GND line)
EPS motor/control unit internal failure
Steering gearbox internal failure (Torque sensor)