P0175 on the 2022 GMC Acadia: V6 Diagnosis
The 2022 GMC Acadia is powered by GM's 3.6L LGX V6 engine producing 310 hp and 271 lb-ft of torque. This engine features direct fuel injection and variable valve timing. As a V6, it has a true Bank 2 configuration, and P0175 means the ECM has detected that Bank 2 is running too rich for the fuel trim system to correct.
At 2-4 years old with 25,000-55,000 miles, the 2022 Acadia's fuel system components are at the age where contamination and early wear begin to cause issues.
Symptoms
- Check engine light on
- Fuel economy below the expected 22-29 MPG range
- Rough idle, especially noticeable when in drive at a stop
- Exhaust smells of gasoline
- Black soot on exhaust tips
- Reduced acceleration response
Causes for the 3.6L V6
1. MAF Sensor Contamination — High Likelihood
GM's 3.6L V6 uses a hot-wire MAF sensor that's susceptible to contamination from PCV oil vapors and environmental debris. At moderate mileage, the MAF element has accumulated enough contamination to degrade its accuracy. The 3.6L's direct injection system generates more crankcase vapors than port-injected engines, which accelerates MAF contamination. A dirty MAF underreads airflow, causing the ECM to deliver excess fuel.
2. O2 Sensor Degradation on Bank 2 — Medium Likelihood
The upstream wideband O2 sensor on Bank 2 provides critical mixture feedback. The 3.6L V6's exhaust system runs hot, particularly under highway cruising conditions. After years of heat cycling, the sensor's response time degrades. A slow sensor gives the ECM outdated data, causing it to overcompensate with fuel. Comparing Bank 1 and Bank 2 sensor data reveals asymmetric degradation.
3. GDI Fuel Injector Issues — Medium Likelihood
The 3.6L uses high-pressure direct injection. By 30,000-50,000 miles, carbon deposits on injector tips begin to alter spray patterns. An injector on Bank 2 that delivers more fuel than commanded pushes that bank's fuel trims negative. An injector balance test identifies specific over-delivering injectors.
4. EVAP Purge Valve — Low Likelihood
GM's EVAP purge valve is a known weak point across the lineup. A stuck-open valve feeds fuel vapors into the intake continuously, enriching the mixture. It's a cheap, easy fix that's worth checking early in the diagnostic process.
Diagnostic Steps
- Scan for all codes with a GM-compatible scanner
- Compare Bank 1 vs Bank 2 fuel trims at idle and 2,000 RPM
- Test MAF sensor output against GM 3.6L specifications
- Monitor O2 sensor waveforms on both banks
- Check EVAP purge valve
- Test fuel pressure at the high-pressure rail
Repair Costs
- MAF sensor: $90–$230
- O2 sensor: $110–$280
- Fuel injector (each): $130–$300
- EVAP purge valve: $50–$140
DIY Options
The 2022 Acadia's engine bay is reasonably accessible for a crossover. MAF sensor and EVAP purge valve replacements are straightforward. O2 sensor access depends on Bank 2's position relative to the firewall — it can be tight on the Acadia. GDI injector work is best handled by professionals. Check warranty coverage first — the 2022 may still be within GM's 3-year/36,000-mile warranty.