What Does P0172 Mean on Your 2023 Kia Soul?
If your 2023 Kia Soul is showing a P0172 code, the engine control module has detected that the engine is running too rich — too much fuel in the air-fuel mixture. Your Soul uses a 2.0-liter Nu MPI inline-4 engine producing 147 horsepower. As an inline-4 with one bank, P0172 indicates the entire engine is receiving excess fuel. The ECM uses oxygen sensor feedback and fuel trim data to maintain the ideal 14.7:1 ratio, and when it maxes out its corrections, this code is stored.
Symptoms You Might Notice
- Check engine light illuminated
- Fuel economy below the rated 31 mpg combined
- Black or dark exhaust smoke
- Rough or shaky idle
- Engine hesitation or stumbling
- Gasoline smell from the exhaust
Common Causes of P0172 on the 2023 Soul
- Contaminated MAF Sensor — The mass airflow sensor can get dirty from road debris, causing incorrect airflow readings and over-fueling by the ECM.
- Stuck Open EVAP Purge Valve — A common Kia issue. The canister purge valve fails open, allowing fuel vapors to continuously enter the intake.
- Failing Oxygen Sensor — The upstream O2 sensor may provide inaccurate feedback, causing incorrect fuel calculations.
- Fuel Injector Issue — Port fuel injectors that drip or fail to close properly add unmetered fuel.
How to Diagnose the Problem
- Check warranty first — The 2023 Soul is under warranty. Your Kia dealer should diagnose and repair at no cost.
- Scan for companion codes — EVAP codes alongside P0172 indicate a purge valve problem.
- Monitor fuel trims — LTFT below -10% confirms the rich condition.
- Test the MAF sensor — At idle, the 2.0L should read about 3-7 g/s.
- Verify O2 sensor operation — Check for proper voltage oscillation between 0.1V and 0.9V.
Repair Options and Estimated Costs
- MAF sensor cleaning — $10-$25 (easy DIY)
- MAF sensor replacement — $85-$210 ($0 under warranty)
- EVAP purge valve replacement — $70-$180 ($0 under warranty)
- Oxygen sensor replacement — $130-$270 ($0 under warranty)
- Fuel injector service — $140-$370 ($0 under warranty)
Your 2023 Soul should be under Kia's full factory warranty. All repairs should be covered.
Prevention Tips
- Follow the Kia maintenance schedule for air filter replacement
- Don't overfill the gas tank
- Use quality fuel
- Report check engine lights to your dealer promptly
- Keep the air intake system clean and properly sealed