P0175 on the 2022 GMC Sierra: V8 Fuel System Diagnosis
The 2022 GMC Sierra 1500 features GM's Gen V small-block V8 engines — the 5.3L L84 (355 hp) and the 6.2L L87 (420 hp) — both equipped with Dynamic Fuel Management (DFM) for cylinder deactivation, direct fuel injection, and variable valve timing. At 2-4 years old with 25,000-60,000 miles, these trucks are entering the mileage window where sensor contamination and early wear can trigger P0175.
Bank 2 on the Sierra's V8 is the passenger side (cylinders 2, 4, 6, 8), and P0175 means that bank is running too rich for the ECM's fuel trim system to handle.
Symptoms
- Check engine light on
- Fuel economy noticeably below the 16-23 MPG range
- Rough or uneven idle
- Rich exhaust odor
- Black soot on exhaust tips
- DFM transitions may feel rougher than normal
- Reduced acceleration and towing performance
Top Causes for the 2022 Sierra V8
1. MAF Sensor Contamination — High Likelihood
After 25,000-60,000 miles of truck use, the MAF sensor has been exposed to significant dust, debris, and PCV oil vapors. GM's direct injection engines generate more crankcase blowby than port-injected engines, which means more oil vapor reaches the MAF sensor. The 5.3L and 6.2L both draw large air volumes, amplifying the impact of even small MAF reading errors. Cleaning may provide temporary relief; replacement with an AC Delco unit ensures lasting accuracy.
2. O2 Sensor Beginning to Wear — Medium Likelihood
At 25,000-60,000 miles, the upstream wideband O2 sensor on Bank 2 has been through thousands of heat cycles. GM V8 exhaust manifolds run very hot, and the sensor is mounted close to these heat sources. Gradual response time degradation causes the ECM to work with outdated exhaust gas data, leading to overcorrection with fuel. Comparing Bank 1 and Bank 2 sensor data side by side reveals asymmetric degradation.
3. GDI Injector Carbon Deposits — Medium Likelihood
Direct injection engines are notorious for carbon buildup on injector tips because the high-pressure fuel spray hits the combustion chamber directly. After 30,000+ miles, carbon deposits can alter spray patterns and cause uneven fuel delivery. If Bank 2 injectors are delivering slightly more fuel due to altered spray patterns, the fuel trims compensate until they can't, triggering P0175.
4. EVAP Purge Valve — Low Likelihood
GM has a well-documented history of EVAP purge valve failures across their truck lineup. The solenoid can stick open, allowing continuous fuel vapor flow into the intake manifold. This is especially noticeable at idle when intake vacuum is highest. Testing by disconnecting the purge line provides a quick diagnostic check.
Diagnosis Steps
- Scan with a GM-compatible scanner (Tech 2, GDS2, or HP Tuners)
- Compare fuel trims between Bank 1 and Bank 2 at idle and 2,000 RPM
- Test MAF sensor readings against GM specifications for the specific engine
- Monitor O2 sensor waveforms — compare response times between banks
- Check EVAP purge valve operation
- Verify fuel pressure at the high-pressure rail
Repair Costs
- MAF sensor: $90–$240
- O2 sensor: $110–$280
- Fuel injector (each): $140–$320
- EVAP purge valve: $50–$140
DIY Potential
The 2022 Sierra has an accessible engine bay for most repairs. MAF sensor and EVAP purge valve replacements are beginner-level DIY jobs. O2 sensor replacement requires working underneath the truck. GDI injector work is more involved due to the high-pressure fuel system and should be handled by experienced technicians. If still under warranty, the dealer is the best option.