P0175 on the 2020 Chevrolet Colorado
The P0175 code on your 2020 Colorado means the ECM has detected a rich condition on Bank 2. The 2020 Colorado is available with the 2.5L four-cylinder (200 hp), the 3.6L V6 (LGZ, 308 hp), and the 2.8L Duramax diesel. On the 3.6L V6, Bank 2 is the cylinder bank opposite from cylinder one. On the 2.5L four-cylinder, the code references a secondary monitoring position. With 40,000-70,000 miles on a 2020 model, wear and contamination are both potential factors.
Midsize Truck Fuel System
The 3.6L V6 in the Colorado uses direct injection only, the same engine family found in the Traverse and other GM vehicles. The 2.5L four-cylinder uses port injection. Each engine has different diagnostic considerations for P0175, though the fundamental issue, excess fuel on Bank 2, is the same. The Colorado's truck use pattern exposes these components to more dust and heat than a typical car.
Symptoms
- Check engine light active
- Fuel economy below the rated 18/25 MPG (V6) or 19/25 MPG (four-cylinder)
- Black or dark exhaust
- Rough idle
- Reduced power for towing or hauling
- Fuel smell from exhaust
Common Causes
1. MAF Sensor Contamination
The Colorado is a midsize truck often used for off-road recreation, camping, and work. Dust exposure is significant, and the MAF sensor accumulates contamination over time. Cleaning with dedicated spray is the first and cheapest diagnostic step, regardless of which engine you have.
2. O2 Sensor Wear
At 40,000-70,000 miles, the upstream O2 sensor on Bank 2 may be degrading. The 3.6L V6 runs at high exhaust temperatures that accelerate sensor wear. On the 2.5L four-cylinder, sensor life is typically longer due to lower exhaust temperatures, but still finite. Test with live data for switching speed.
3. Direct Injector Carbon Buildup (V6)
The 3.6L V6's direct injection system leads to carbon deposits on injector tips and intake valves. By 50,000+ miles, these deposits can affect fuel delivery accuracy. The 2.5L's port injection system is less prone to carbon buildup on valves but can still have injector seal issues.
4. Fuel Pressure Issue
On the V6, the high-pressure fuel pump is cam-driven. If the pump's regulator allows excess pressure, all injectors deliver more fuel than commanded. This typically affects both banks but Bank 2 may trigger first. Check fuel rail pressure against specification.
Diagnostic Steps
- Identify your engine (2.5L or 3.6L) and scan for all codes
- Monitor Bank 1 and Bank 2 fuel trims (V6) or overall trims (four-cylinder)
- Clean the MAF sensor
- Test the upstream O2 sensor with live data
- Check for misfire codes pointing to specific injectors
- Verify fuel pressure at the rail
- On the V6, consider carbon buildup if other causes are ruled out
Repair Costs
O2 sensor: $120-$300. MAF cleaning: under $15. Injector cleaning: $100-$200. Injector replacement: $200-$550 (V6) or $120-$300 (four-cylinder). Carbon cleaning: $300-$600. The 2020 Colorado's powertrain warranty extends through 2025 at 60,000 miles.
Priority
Fix within two to three weeks. The Colorado's fuel economy matters for truck owners who put on miles. Catalytic converter replacement on the Colorado V6 costs $800-$2,000. Protecting the converter is the primary reason to address P0175 promptly.