2021 Infiniti P0172: What It Means & Is It Safe to Drive?
P0172 on the 2021 Infiniti: System Too Rich (Bank 1). Here's what it means, what usually causes it, what repairs typically cost, and whether it's safe to keep driving.
PowertrainMedium urgency
What this code means
Too much fuel relative to air. O2 sensor detects low oxygen in exhaust; PCM is reducing fuel trim.
Common causes on the 2021 Infiniti
- Faulty MAF or O2 sensor
- Leaking fuel injector(s)
- High fuel pressure
- Faulty purge valve stuck open
Symptoms
- Check Engine Light
- Rich smell, black smoke
- Poor fuel economy
- Rough idle possible
Typical fixes
- Replace MAF or O2 sensor
- Test fuel pressure and injectors
- Replace purge valve if stuck open
Repair cost range
For a 2021 Infiniti, repairs for P0172 typically fall between $100 and $600, depending on the root cause and labor rates in your area.
Known issues on Infiniti
Infiniti VQ bank 1 rich condition. A leaking fuel pressure regulator is the most common cause on G35 and G37. A faulty MAF sensor reading low (causing the ECU to over-fuel) is the secondary cause; compare MAF readings to spec before replacing the regulator.
Most commonly affected models
G35 2003–2007G37 2008–2013FX35 2003–2008