Does C120D mean the corner radar sensor is bad on my Kia EV6?

No. On the EV6, the CR module reports C120D when it detects an electrical fault in the left warning indicator circuit. The definition points to an open circuit or a short to battery. Prove the circuit first with connector checks and a loaded output test. Condemn the module only after you verify power, ground, and output integrity.

Can my scan tool still communicate with the CR (Corner Radar) module, and why does that matter?

Yes, you often can still communicate with the CR module even when C120D sets. Communication confirms the module stays online and can report data and codes. That steers you toward an output circuit issue, not a network outage. If the scan tool cannot connect, diagnose power, ground, and network lines to the module before chasing the indicator wiring.

Will I need calibration after repairing C120D?

If you only repair wiring, connectors, or the indicator load, calibration usually is not required. If you replace the CR (Corner Radar) module or any radar sensor hardware, plan on a calibration or initialization procedure using Kia-approved scan tooling and targets. Perform that step before trusting ADAS warnings. Confirm the system reports “normal” status after calibration.

How do I confirm the repair is complete and the code will not return?

Clear the code, then command the left warning indicator with the scan tool if bi-directional controls exist. Next, road-test the vehicle under conditions that make the warning indicator operate. Enable criteria vary by Kia platform and feature set, so follow service information for exact conditions. Re-scan afterward and confirm no pending or history C120D returns.

What does “open or short to battery” mean for real-world troubleshooting?

An open circuit means the CR module cannot push current through the indicator path, often from a broken wire, poor terminal tension, or corrosion. A short to battery means the control wire touches a powered feed, so the circuit stays high when it should not. Use a wiring diagram to identify the control pin, then test for continuity, shorts, and voltage under load.

C120D Kia – Left warning indicator circuit open or short to

C1101 Battery voltage high
C1102 Battery voltage low
C1200 Left front vehicle speed sensor circuit open/short
C1205 Right front wheel speed sensor (VSS) invalid / no…
C1259 Steering angle sensor (SAS) electrical fault
C1260 Steering angle sensor (SAS) circuit signal
C1268 Circuit leakage fail
C1283 Lateral G-Sensor/Longitudinal G-Sensor/Yaw rate sensor (YRS) signal error

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