2005 Acura P0172: What It Means & Is It Safe to Drive?
P0172 on the 2005 Acura: 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 2005 Acura
- 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 2005 Acura, repairs for P0172 typically fall between $100 and $600, depending on the root cause and labor rates in your area.
Known issues on Acura
Acura J35 V6 P0172 rich Bank 1 is typically a stuck EVAP purge valve or a leaking fuel injector. On the turbocharged RDX K23A1, a boost leak can cause ECU over-compensation resulting in a rich condition—check boost hose connections alongside the purge valve.
Most commonly affected models
TL J35Z 2004–2008MDX J35Z 2003–2006RDX K23A1 Turbo 2007–2012