P121C MINI Possible Causes
- Faulty nitrogen oxide (NOx) sensor
- Nitrogen oxide (NOx) sensor harness is open or shorted
- Poor electrical connection in the nitrogen oxide (NOx) sensor circuit
How to Fix P121C MINI Code?
Start by checking the “possible causes” listed above. Visually inspect the corresponding wiring harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.
Possible Symptoms
- Engine light on (or engine service warning light soon)
P121C MINI Meaning
The Engine Control Module (ECM) monitors the nitrogen oxide (NOx) sensor. The ECM sets the OBDII code when the nitrogen oxide sensor does not meet factory specifications.