What Does P0172 Mean on Your 2022 Cadillac XT6?
A P0172 code on your 2022 Cadillac XT6 means the engine control module has detected a rich air-fuel mixture on Bank 1. The 2022 XT6 is powered by a 3.6-liter naturally aspirated V6 engine producing 310 horsepower, paired with a 9-speed automatic transmission. Bank 1 is the cylinder bank containing cylinder number 1.
The 3.6L V6 uses direct injection for precise fuel delivery. Running rich means there is too much fuel in the combustion mixture relative to the air, which affects performance, economy, and emissions.
Symptoms You May Notice
- Check engine light on
- Fuel economy below the rated 18/25 mpg
- Rough or shaky idle
- Black smoke from the exhaust
- Fuel smell at the tailpipe
- Reduced power
- Potential misfires on Bank 1
Common Causes of P0172 on the 2022 Cadillac XT6
- Dirty MAF Sensor - The mass airflow sensor can accumulate dust and oil film, causing it to underread airflow and trigger over-fueling.
- EVAP Purge Valve Stuck Open - A common GM issue where the purge valve fails to close, continuously feeding fuel vapors into the intake.
- Leaking Bank 1 Fuel Injector - Direct injection injectors can develop leaks at the high operating pressures used by the 3.6L V6.
- Failing Bank 1 Upstream O2 Sensor - A degraded oxygen sensor provides incorrect readings, causing the ECM to over-fuel.
How to Diagnose P0172
- Scan all codes - Check for P0175, EVAP, MAF, or O2 sensor companion codes.
- Review Bank 1 fuel trims - Negative LTFT beyond -10% confirms excess fueling.
- Clean and test the MAF - Best first diagnostic step.
- Test the purge valve - Verify proper operation.
- Monitor O2 sensors - Check Bank 1 Sensor 1 response.
- Test fuel injectors - Check for leaks on Bank 1 cylinders.
Repair Options and Cost Breakdown
- MAF Cleaning - $12-$28 DIY.
- MAF Replacement - $140-$320 parts and labor.
- EVAP Purge Valve - $80-$210 parts and labor.
- Fuel Injector Replacement - $280-$550 per injector.
- O2 Sensor Replacement - $180-$370 parts and labor.
Most repairs cost $120 to $380. The XT6 shares many components with other GM crossovers, keeping costs reasonable.
Can You DIY This Repair?
MAF cleaning, air filter replacement, and purge valve replacement are all DIY-friendly tasks. The XT6 engine bay offers decent access. Fuel injector replacement on the direct injection system requires professional tools and expertise.
Prevention Tips
- Replace the air filter every 15,000-20,000 miles
- Use quality fuel from top-tier stations
- Add fuel system cleaner every 10,000 miles
- Follow the GM-recommended maintenance schedule
- Address check engine lights promptly to protect catalytic converters