What Does P0172 Mean on Your 2022 Nissan Altima?
A P0172 code on the 2022 Nissan Altima indicates the engine control module has detected a rich condition on Bank 1. The 2022 Altima uses the 2.5L QR25DE naturally aspirated four-cylinder engine making 188 horsepower. As an inline-four, it has only one bank.
A rich condition means excess fuel relative to air in the combustion mixture. This wastes gas, can foul spark plugs, and stresses the catalytic converter. Getting it diagnosed and fixed promptly saves money on fuel and prevents more expensive repairs.
Common Symptoms You May Notice
- Check engine light illuminated
- Worse fuel economy
- Rough or uneven idle
- Black smoke from the exhaust
- Fuel odor at the tailpipe
- Sluggish acceleration
Top Causes of P0172 on the 2022 Altima
- Dirty MAF sensor - The mass airflow sensor is the leading cause of P0172 on Nissan vehicles. Contamination causes it to underread airflow, resulting in over-fueling.
- Failing upstream O2 sensor - The oxygen sensor may degrade over time, sending incorrect data for fuel trim adjustments.
- Leaking fuel injector - A fuel injector that does not seal properly delivers excess fuel.
- Stuck-open EVAP purge valve - A purge valve that stays open sends continuous fuel vapors into the intake.
How to Diagnose the Problem
Scan for codes and review freeze frame data. Check STFT and LTFT values. Negative LTFT past -10% confirms the rich condition.
Clean the MAF sensor with proper MAF cleaner spray. The MAF on the Altima is in the intake tube, easy to access. Monitor the upstream O2 sensor; it should oscillate between 0.1V and 0.9V.
Check the EVAP purge valve for proper operation. Test fuel pressure if other components check out.
Repair Options and Cost Estimates
- MAF sensor cleaning or replacement: Cleaning under $10. New sensor $35-$120 plus $35-$75 labor.
- O2 sensor replacement: Parts $35-$120. Labor $55-$110.
- Fuel injector replacement: Parts $25-$70 per injector. Labor $120-$265.
- EVAP purge valve: Parts $20-$45. Labor $35-$80.
Can You Fix This Yourself?
The Altima is very DIY-friendly. MAF cleaning takes 15 minutes. O2 sensor replacement is moderate. Fuel injector replacement is doable for intermediate DIYers. EVAP valve replacement is straightforward.
Prevention Tips
- Replace the air filter every 15,000-20,000 miles
- Use quality fuel
- Run fuel system cleaner every 5,000 miles
- Address check engine lights promptly