What Does P0172 Mean on Your 2020 Chevrolet Colorado?
A P0172 code on the 2020 Chevrolet Colorado means the engine control module has detected a rich condition on Bank 1. The 2020 Colorado offers three gasoline engines: the 2.5L four-cylinder (200 hp), the 3.6L V6 (308 hp), and the 2.8L Duramax turbo-diesel (which does not set P0172). On the 3.6L V6, Bank 1 is the rear bank. The 2.5L four-cylinder has only one bank.
Running rich means excess fuel is entering the combustion chambers. This wastes gas, fouls spark plugs, and can damage catalytic converters. For a work truck, poor fuel economy really adds up over time.
Common Symptoms You May Notice
- Check engine light on
- Worse gas mileage
- Rough or uneven idle
- Black smoke from the exhaust
- Fuel smell at the tailpipe
- Hesitation during acceleration
Top Causes of P0172 on the 2020 Colorado
- Dirty MAF sensor - Truck driving often involves dusty conditions that contaminate the MAF sensor, causing it to underread airflow and trigger over-fueling.
- Faulty upstream O2 sensor - The Bank 1 upstream oxygen sensor can degrade, providing incorrect voltage readings to the ECM.
- Leaking fuel injector - The 3.6L V6 uses direct injection. A leaking injector on the rear bank delivers excess fuel.
- EVAP purge valve stuck open - A malfunctioning purge valve sends fuel vapors into the intake continuously.
How to Diagnose the Problem
Scan codes and check freeze frame data. Look at STFT and LTFT for Bank 1. Negative LTFT past -10% confirms the rich condition.
Replace the air filter if dirty and clean the MAF sensor. On the Colorado, the MAF is in the air intake tube between the filter box and throttle body.
Monitor the Bank 1 upstream O2 sensor. It should oscillate between 0.1V and 0.9V. Check fuel pressure if other components test normal.
Repair Options and Cost Estimates
- MAF sensor cleaning or replacement: Cleaning under $10. New sensor $45-$155 plus $45-$90 labor.
- O2 sensor replacement: Parts $45-$140. Labor $75-$145.
- Fuel injector replacement: Parts $35-$100 per injector. Labor $185-$395.
- EVAP purge valve: Parts $25-$55. Labor $45-$95.
Can You Fix This Yourself?
MAF cleaning is simple. O2 sensor replacement is moderate. The Colorado's engine bay is reasonably accessible for a midsize truck. Fuel injector work on the direct injection 3.6L is more advanced.
Prevention Tips
- Replace the air filter more often if you drive in dusty conditions
- Use quality fuel to keep injectors clean
- Run fuel system cleaner every 5,000 miles
- Address check engine lights promptly