Understanding the P0172 Code on Your 2024 Volvo XC90
A P0172 code on your 2024 Volvo XC90 means the powertrain control module has detected an overly rich air-fuel mixture on Bank 1. The 2024 XC90 is equipped with Volvo's B5 or B6 mild-hybrid 2.0-liter four-cylinder engine with an integrated starter-generator, or the Recharge T8 plug-in hybrid. These powertrains use advanced fuel management, and when the system detects too much fuel relative to air, it sets this code. Ignoring it can lead to catalytic converter damage and increased emissions.
Symptoms You May Notice
- Check engine light on the instrument cluster
- Noticeably worse fuel economy below the expected 23-27 MPG range
- Black or dark exhaust smoke
- Rough or uneven idle
- Fuel odor from the tailpipe
- Possible hesitation or stumbling during acceleration
Most Common Causes of P0172 on the 2024 XC90
- Contaminated Mass Airflow (MAF) Sensor - The MAF sensor in the 2024 XC90's intake tract can become fouled by oil vapors from the PCV system or environmental debris, causing incorrect airflow readings and excess fuel delivery.
- Faulty or Leaking Fuel Injectors - High-pressure direct fuel injectors on the 2.0L engine can develop leaks or fail to close properly, delivering too much fuel to Bank 1 cylinders.
- Worn or Failing Upstream O2 Sensor - The pre-catalytic converter oxygen sensor on Bank 1 monitors exhaust gas composition. If it reads incorrectly, the ECM overcompensates by enriching the mixture.
- Restricted Air Intake or Dirty Air Filter - A clogged air filter element reduces airflow into the engine, disrupting the air-fuel ratio and triggering a rich condition code.
How to Diagnose the Problem
Begin with an OBD-II scan to confirm P0172 and check for any additional codes that might point to a related issue. Review freeze frame data to see the conditions when the code was set. Check fuel trim values for Bank 1. Long-term fuel trim readings below -10% indicate the ECM has been trying to compensate for a persistent rich condition. Visually inspect the MAF sensor and air filter. Use MAF-specific cleaner if contamination is found. Test fuel pressure with a gauge to rule out a faulty fuel pressure regulator. Monitor the upstream O2 sensor waveform using a scan tool to verify it is switching between rich and lean states at the proper rate. Inspect fuel injectors for proper operation using a noid light or balance test.
Repair Options and What to Expect
On the 2024 XC90, the most common fix is cleaning or replacing the MAF sensor. This is accessible in the engine bay and can often be done at home with a MAF cleaner spray. Fuel injector replacement is more labor-intensive on the direct-injection 2.0L engine and is usually best left to a qualified Volvo technician or European car specialist. O2 sensor replacement requires accessing the sensor from underneath the vehicle. Air filter replacement is a simple DIY task that takes less than 10 minutes.
Estimated Repair Costs
- MAF Sensor Cleaning or Replacement: $150 - $380 (parts and labor)
- Fuel Injector Replacement: $350 - $750 (parts and labor)
- Upstream O2 Sensor Replacement: $220 - $480 (parts and labor)
- Air Filter Replacement: $30 - $65 (DIY)
Volvo dealership labor rates typically run $160-$210 per hour. Independent shops specializing in European vehicles can often complete the same work for 25-35% less.
Prevention Tips
- Change the engine air filter every 15,000 miles or as recommended in the Volvo service schedule
- Use premium fuel as specified in the owner's manual to keep injectors clean
- Have the MAF sensor inspected during routine maintenance visits
- Respond to check engine lights quickly to prevent catalytic converter damage
- Keep up with scheduled maintenance intervals per your Volvo warranty requirements