P123E 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 is code P123E repaired?
Start by checking the “Possible Causes” listed above. Visually inspect the wiring harness and related connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.
Possible Symptoms
- Check Engine Light on (or Service Engine Soon warning light)
P123E Meaning
The Engine Control Module (ECM) monitors the nitrogen oxide sensor. The ECM sets the OBDII code when the nitrogen oxide sensor does not meet factory specifications.