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P2203 — NOx Sensor Circuit High Bank 1
SeriousAftertreatmentPower derate likely — plan to stop soon
Seen on: Heavy Truck/Diesel
NOx Sensor Circuit High Bank 1. Common causes: NOx sensor signal high.
Don't risk it — get a diesel tech on the truck.
Look up listed providers near you and give them this code when you call.
How serious is it?
Serious. Power derate likely — plan to stop soon.
Most likely causes
- NOx sensor signal high
- Open circuit
- failed sensor
First moves (roadside)
- Check for open in signal wire
- replace sensor
FAQ
What does P2203 mean?
NOx Sensor Circuit High Bank 1. Common causes: NOx sensor signal high.
How serious is P2203?
Serious — Power derate likely — plan to stop soon.
What's the most likely cause of P2203?
The most common cause is: NOx sensor signal high. Other possibilities include Open circuit; failed sensor.
Can I keep driving with P2203?
Power derate likely — plan to stop soon. When in doubt, get a qualified mobile diesel tech on the truck before continuing.
Throwing this code right now?
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General diagnostic guidance for diesel engines (Cummins, Detroit, PACCAR, Volvo, Mack and more). Not a substitute for a scan-tool diagnosis on your specific truck.