P2203
ModerateP2203 — NOx Sensor Circuit High, Bank 1 Sensor 1
Description
What the Code Means
P2203 — high signal level from the NOx (nitrogen oxides) sensor, bank 1, sensor 1. The code means the voltage on the sensor signal wire exceeds the allowable threshold set by the DME.
The NOx sensor is part of the selective catalytic reduction (SCR) system and monitors nitrogen oxide concentration in the exhaust. The DME uses its readings to control urea (AdBlue) injection and to assess conversion efficiency. With a high signal level, the DME flags the data as unreliable and may limit SCR system operation.
Possible causes: a faulty sensor, an open or shorted wire, or a power supply problem at the sensor.
Symptoms
Symptoms
- Increased fuel consumption.
- Problems with the SCR system.
- Check Engine light comes on.
Causes and fixes
Diagnosis and Repair
- Read the fault codes with ISTA or INPA and check for related SCR system errors.
- Check the NOx sensor and its wiring: inspect the connectors for corrosion and damage, check wire continuity, and test for a short to ground or power.
- Replace the NOx sensor if needed.