P0172
Get Serviced SoonFix: High — schedule within a weekSystem Too Rich (Bank 1) — Engine is receiving too much fuel or too little air. Opposite of P0171.
Dashboard light triggered
Check Engine LightWhat to do
Check for dirty MAF, leaking fuel injectors, or faulty O2 sensor. May cause poor fuel economy and emissions issues.
Common causes
- Dirty or faulty MAF sensor
- Leaking fuel injector(s)
- Faulty oxygen sensor
- High fuel pressure (bad regulator)
Estimated repair cost
$100–$800
Exact cost depends on the cause, your vehicle, and labor rates in your area.
What to tell your mechanic
Use this script so you sound informed and get a clear diagnosis before agreeing to repairs:
“Code P0172, system too rich bank 1. Can you inspect the MAF, fuel injectors, and O2 sensors? I'd like a proper diagnosis before we swap parts.”
About the Check Engine Light
Code P0172 triggers the Check Engine Light. Indicates an issue with the engine or emissions system. Could range from a loose gas cap to a serious engine misfire.
Read full Check Engine Light guideFrequently asked questions
- What does OBD code P0172 mean?
- System Too Rich (Bank 1) — Engine is receiving too much fuel or too little air. Opposite of P0171.
- What dashboard light does P0172 trigger?
- P0172 triggers the Check Engine Light.
- How serious is P0172?
- Severity: yellow. Fix priority: High — schedule within a week.
- How much does it cost to fix P0172?
- Repair costs typically range from $100–$800. The exact cost depends on the root cause and your vehicle.
Related OBD codes (same dashboard light)
These codes also trigger the Check Engine Light: