What Does P0172 Mean on Your 2023 Chevrolet Tahoe?
When your 2023 Chevrolet Tahoe throws a P0172 code, the powertrain control module is reporting that Bank 1 is running too rich. The 2023 Tahoe is available with the 5.3L EcoTec3 V8 (355 hp), the 6.2L EcoTec3 V8 (420 hp), or the 3.0L Duramax diesel. P0172 only applies to the gasoline V8 engines. Bank 1 on these V8s is the driver side of the engine.
Both gasoline V8s use Dynamic Fuel Management with combined port and direct injection. A rich condition means Bank 1 is receiving more fuel than the stoichiometric ratio calls for. This wastes fuel on a vehicle that already has a large fuel appetite, and can damage the catalytic converters, which are costly on the Tahoe.
Common Symptoms You May Notice
- Illuminated check engine light
- Reduced miles per gallon
- Rough or surging idle
- Black smoke from the exhaust
- Fuel odor at the tailpipe
- Sluggish performance or hesitation
Top Causes of P0172 on the 2023 Tahoe
- Contaminated MAF sensor - Road dust and debris contaminate the MAF sensing element, causing underreported airflow and excess fuel injection.
- Leaking fuel injector - With both port and direct injectors, there are more potential failure points. A leaking Bank 1 injector dumps extra fuel.
- Degraded upstream O2 sensor - The Bank 1 Sensor 1 oxygen sensor can become slow or inaccurate, feeding bad data to the PCM.
- Fuel pressure regulator malfunction - Excessive fuel pressure pushes too much fuel through all injectors.
How to Diagnose the Problem
Scan for codes and check freeze frame data. Look at Bank 1 STFT and LTFT. Negative LTFT past -10% confirms the engine is running rich on Bank 1.
Start with the air filter and MAF sensor. Clean the MAF with dedicated cleaner. Monitor the Bank 1 upstream O2 sensor; it should oscillate between 0.1V and 0.9V. Check fuel pressure at the rail.
If only Bank 1 shows rich fuel trims, the issue is likely specific to Bank 1 components. If both banks show rich, suspect the MAF sensor or fuel pressure system.
Repair Options and Cost Estimates
- MAF sensor cleaning or replacement: Cleaning under $10. New sensor $55-$185 plus $50-$105 labor.
- Fuel injector replacement: Parts $40-$105 per injector. Labor $230-$485.
- O2 sensor replacement: Parts $55-$170. Labor $85-$170.
- Fuel pressure regulator: Parts $50-$140. Labor $115-$265.
Can You Fix This Yourself?
MAF cleaning is straightforward on the Tahoe. O2 sensor replacement is moderate. Fuel injector work is advanced. The 2023 Tahoe may still be under warranty, so dealer service is often the best option.
Prevention Tips
- Replace the air filter on schedule or sooner in dusty conditions
- Use Top Tier gasoline for cleaner injectors
- Add fuel system cleaner every 5,000-7,000 miles
- Respond to check engine lights quickly