Ageing or contaminated NOx sensor; Exhaust leak near the sensor; Faulty sensor control module; Wiring or connector problems; EGR faults causing NOx values far from the model.

NOx sensors

P2201 NOx Sensor Circuit Range/Performance (Bank 1 Sensor 1)

Q: What does P2201 mean?

NOx Sensor Circuit Range/Performance (Bank 1 Sensor 1). The ECU checks the upstream NOx sensor reading for plausibility against modelled engine-out NOx and other sensor values. P2201 is set when the signal is outside the expected range or does not respond correctly.

The ECU checks the upstream NOx sensor reading for plausibility against modelled engine-out NOx and other sensor values. P2201 is set when the signal is outside the expected range or does not respond correctly.

Common causes

Ageing or contaminated NOx sensor
Exhaust leak near the sensor
Faulty sensor control module
Wiring or connector problems
EGR faults causing NOx values far from the model

Typical symptoms

Check engine light (MIL) on
SCR operation limited or disabled
Countdown to engine start restriction on some vehicles

P2201 and NuoVolta

If the SCR/AdBlue system and its NOx sensors have been removed for off-road or motorsport use, where permitted by law, the NuoVolta AdBlue / SCR / NOx Removal solution adjusts the ECU calibration and the DTC removal feature can disable this code. On a working system, check for exhaust leaks and test the sensor first.

AdBlue / SCR / NOx Removal Available for 121 ECUs

Related codes

P2200NOx Sensor Circuit (Bank 1 Sensor 1) P229FNOx Sensor Circuit Range/Performance (Bank 1 Sensor 2) P2BADNOx Exceedance - Root Cause Unknown

Diagnose and repair real faults first. Removing or disabling emission systems is only permitted where allowed by law, for example for off-road or motorsport use.