What Does P0172 Mean on Your 2022 GMC Acadia?
A P0172 code on your 2022 GMC Acadia means the engine control module has detected an overly rich fuel mixture on Bank 1. The 2022 Acadia is equipped with the 3.6L LGX V6 engine producing 310 hp. On this V6, Bank 1 is typically the rear cylinder bank (cylinders 1, 3, 5).
The 3.6L V6 is a proven and reliable engine, so P0172 usually points to a specific sensor or component issue rather than a fundamental engine problem. Getting it diagnosed promptly prevents catalytic converter damage and restores fuel economy.
Symptoms You Might Notice
- Check engine light on
- Decreased fuel economy
- Rough or unsteady idle
- Fuel smell from the exhaust
- Black soot buildup on the tailpipe
- Slight hesitation on acceleration
Common Causes of P0172 on the 2022 GMC Acadia
- Dirty MAF Sensor — The MAF sensor on the 3.6L V6 is susceptible to contamination from oil or debris, causing airflow under-reporting.
- Stuck-Open Purge Valve — A common GM issue. The EVAP purge solenoid sticks open, allowing excess fuel vapors into the intake manifold.
- Failing Upstream O2 Sensor (Bank 1) — A slow-responding or biased O2 sensor sends incorrect data to the ECM.
- Leaking Fuel Injector — The 3.6L uses port fuel injection, and aging injectors can develop seal failures.
How to Diagnose the Problem
- Read all stored codes — Look for P0175 (Bank 2 rich) or related sensor codes.
- Check fuel trims — Compare Bank 1 and Bank 2 LTFT values.
- Test MAF sensor — Verify readings against factory specs at idle and under load.
- Test purge valve — Use a scan tool to command the valve open and closed.
- Monitor O2 sensor — Check for proper voltage switching on Bank 1 Sensor 1.
- Test fuel pressure and injectors — Verify system pressure and check for leaking injectors.
Repair Options and Cost Estimates
- MAF Sensor Cleaning — DIY: $10-$15. Shop: $55-$110.
- MAF Sensor Replacement — Parts: $75-$180, labor: $55-$110. Total: $130-$290.
- Purge Valve Replacement — Parts: $20-$55, labor: $55-$110. Total: $75-$165.
- O2 Sensor Replacement — Parts: $80-$190, labor: $90-$165. Total: $170-$355.
- Fuel Injector Replacement — Parts: $40-$120 each, labor: $180-$350. Total: $220-$470.
Can You Fix This Yourself?
MAF sensor cleaning is quick and easy — remove, spray, dry, reinstall. The purge valve is also accessible and replaceable with basic tools. O2 sensor work requires getting under the vehicle. Injector work on the 3.6L V6 is more involved due to the intake manifold's positioning but is still doable for experienced DIYers.
Prevention Tips
- Replace the air filter at recommended intervals
- Avoid oiled aftermarket air filters
- Use Top Tier gasoline to keep fuel system components clean
- Follow GM's maintenance schedule