What Does P0172 Mean on Your 2022 Honda Accord?
The 2022 Honda Accord uses either a 1.5L turbocharged inline-4 producing 192 hp or a 2.0L turbocharged inline-4 making 252 hp (Sport 2.0T and Touring trims). If your scanner pulled P0172, the ECM has detected that Bank 1 is running rich, meaning there is excess fuel in the combustion mixture. Since both engines are inline-4 designs, Bank 1 covers all four cylinders.
This code means the oxygen sensor downstream sees too much unburned fuel in the exhaust gases. The ECM has tried to compensate by reducing fuel delivery, but the mixture is still too rich beyond its correction range.
Common Symptoms You Might Notice
- Illuminated check engine light
- Worse fuel economy than usual
- Strong gasoline or rotten egg smell from exhaust
- Black soot deposits on the tailpipe
- Rough or uneven idle
- Reduced power or throttle response
Top Causes of P0172 on the 2022 Accord
- Dirty MAF Sensor (35% likelihood): The mass airflow sensor sits in the intake tract between the air filter and turbo. Oil mist from the PCV system and road grime can coat the hot-wire element, causing it to underreport airflow and trigger over-fueling.
- Faulty Upstream O2 Sensor (25% likelihood): The upstream O2 sensor monitors exhaust gases and provides real-time feedback for fuel trim adjustments. A failing sensor can report inaccurate data.
- Stuck Open Purge Valve (20% likelihood): The EVAP purge valve controls fuel vapors from the charcoal canister. If it sticks open, excess fuel vapor enters the intake, enriching the mixture beyond the ECM's ability to compensate.
- Intake Leak or Boost Leak (20% likelihood): On turbocharged Accords, a leak in the charge piping or intercooler can cause erratic MAF readings, leading to incorrect fueling.
How to Diagnose P0172 on Your 2022 Accord
- Check for additional codes. P0172 often appears alongside other codes like P0101 (MAF issue) or P0441/P0446 (EVAP system). Related codes help narrow the diagnosis.
- Inspect and clean the MAF sensor. Remove the sensor from the intake tube and spray the element with MAF-specific cleaner. Allow it to air dry completely.
- Monitor fuel trims with a scan tool. LTFT values below -10% confirm a sustained rich condition the ECM is trying to correct.
- Check the EVAP purge valve. With the engine idling, disconnect the purge valve hose. If idle quality changes significantly, the valve may be stuck open.
- Inspect turbo charge piping. On 2.0T models, check all the intercooler pipes and couplers for leaks. A boost leak can cause erratic fuel delivery.
Repair Options and Costs
- MAF sensor cleaning: $10 DIY, $60-$100 at a shop
- MAF sensor replacement: $130-$260 parts and labor
- O2 sensor replacement: $170-$350 parts and labor
- EVAP purge valve replacement: $100-$250 parts and labor
- Boost/intake leak repair: $75-$300 depending on location and severity
Can You DIY This Repair?
Cleaning the MAF sensor is one of the easiest DIY jobs on the 2022 Accord and should be your first step. Checking and replacing the air filter is even simpler. The purge valve is accessible and a moderate DIY job. O2 sensor replacement requires getting under the car and using a special socket, but is manageable for someone with basic mechanical skills. Boost leak diagnosis on the 2.0T requires a smoke machine or careful inspection and is better left to a shop.
Prevention Tips
- Replace the air filter at recommended intervals (every 15,000-20,000 miles)
- Clean the MAF sensor every 30,000 miles as preventive maintenance
- Use quality gasoline, preferably top-tier brands
- For 2.0T models, inspect charge piping connections at oil change intervals
- Do not ignore check engine lights, as catalytic converter damage from rich running is expensive