Symptoms of P0041
- Check-engine light on, sometimes with rough or uneven running.
- Hesitation, surging, or a noticeable change in fuel economy.
- Occasionally hard starting or a smell of unburnt fuel.
Common causes of P0041
- A failing or contaminated sensor (MAF, MAP, oxygen or air-fuel sensor).
- Intake or vacuum leaks, or an exhaust leak near an upstream sensor.
- Wiring, connector, or fuel-delivery problems that skew the reading.
Useful checks before replacing parts
- Compare downstream oxygen sensor responses on both banks during fuel changes, catalyst monitor activity, and deceleration fuel cut.
- Inspect downstream sensor connectors, harness routing after exhaust service, bank identification, and any repaired or extended wiring.
- Check for exhaust leaks, catalyst faults, fuel trim imbalance, and scan-tool labeling errors before confirming swapped signals.
Related OBD-II codes
These nearby fuel / air entries can help compare wording and pin down the fault area.