NOx Sensor Circuit Bank 1
The Powertrain Control Module (PCM) has detected an electrical malfunction or out-of-range voltage in the Nitrogen Oxide (NOx) sensor circuit for Bank 1. This sensor is responsible for monitoring the level of NOx emissions in the exhaust to optimize the selective catalytic reduction (SCR) system or lean-burn emissions controls.
While this code will not typically cause the vehicle to stall or strand you, it indicates a failure in the emissions system. Prolonged driving can lead to failed emissions tests, reduced fuel economy, and potential issues with the diesel particulate filter (DPF) or SCR systems.
Common symptoms
- Illuminated Check Engine Light (MIL)
- Failed vehicle emissions test
- Slight decrease in fuel efficiency
- Possible reduction in engine performance or entering limp mode (especially on diesel vehicles)
- Excessive exhaust smoke or soot under heavy acceleration
Likely causes
- Faulty NOx sensor on Bank 1
- Damaged, corroded, or loose wiring and connectors in the NOx sensor circuit
- Exhaust leaks upstream of the NOx sensor
- Contaminated or degraded NOx sensor element (e.g., from excessive soot)
- Faulty Powertrain Control Module (PCM) or SCR controller (rare)
What to check before replacing parts
Visually inspect the wiring and connectors for the Bank 1 NOx sensor
Look for: Look for melted wires, corrosion, or loose connections at the sensor harness that could cause an open or short circuit.
Monitor NOx sensor data using a professional scan tool
Look for: Look for the NOx sensor voltage or ppm readings to be stuck, erratic, or completely out of the expected range compared to manufacturer specifications.
Inspect the exhaust system for leaks upstream of the NOx sensor
Look for: Look for soot trails, hissing sounds, or physical cracks in the exhaust pipe that could introduce unmetered oxygen and skew the sensor readings.
Perform a multimeter resistance and continuity test on the sensor circuit
Look for: Look for open circuits, high resistance, or shorts to ground in the wiring between the NOx sensor connector and the PCM.
Check for other related emissions or exhaust codes
Look for: Look for SCR, DPF, or other exhaust sensor codes that might indicate a broader emissions system failure rather than an isolated NOx sensor circuit issue.
This page explains the generic P2200 definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
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