What Does P0172 Mean on Your 2022 Jeep Grand Wagoneer?
When your 2022 Jeep Grand Wagoneer triggers a P0172 code, the powertrain control module has detected that Bank 1 of the 6.4L HEMI V8 is running too rich. The Grand Wagoneer's 6.4-liter naturally aspirated V8 produces an impressive 471 horsepower and uses a sophisticated fuel injection system with both port and direct injection (known as the Fuel Saver Technology system with cylinder deactivation). When the air-fuel ratio tips too far toward the rich side on Bank 1, this code sets.
Given the Grand Wagoneer's premium price tag, repairs can be more expensive than on other Jeep models. Let us break down the causes and get you on the right track.
Symptoms You Might Notice
- Check engine light on
- Reduced fuel economy, which is already noticeable in a full-size SUV
- Black exhaust smoke
- Strong fuel odor from the tailpipe
- Rough idle or slight engine vibration
- Reduced power or delayed throttle response
Common Causes of P0172 on the 2022 Grand Wagoneer
- Faulty MAF Sensor - The mass airflow sensor on the 6.4L HEMI can become contaminated, leading to inaccurate airflow readings. The ECU then adds more fuel than needed.
- Leaking Fuel Injector - With both port and direct injection systems, the Grand Wagoneer has more injectors that can potentially fail. A leaking injector on the Bank 1 side delivers excess fuel.
- Defective Upstream O2 Sensor - The Bank 1 Sensor 1 oxygen sensor provides real-time air-fuel ratio feedback. If it reads incorrectly, fuel trims go out of range.
- High Fuel Pressure - The dual-injection system operates with both low-pressure and high-pressure fuel circuits. A faulty pressure regulator on either circuit can cause over-fueling.
How to Diagnose the Problem
Use a professional-grade scan tool to access the PCM data. The 6.4L HEMI's dual-injection system requires a scanner capable of reading both port and direct injection parameters. Check STFT and LTFT for Bank 1 and compare to Bank 2. Negative fuel trims below -10 percent on Bank 1 only suggest a bank-specific issue.
Start by inspecting the air filter and cleaning the MAF sensor. Check intake boots and connections for air leaks. If the problem persists, test the O2 sensor waveform and check fuel pressure on both the low-pressure and high-pressure circuits. Given the complexity of this engine, dealer-level diagnostics may be warranted.
Repair Options and Cost Breakdown
- Air filter replacement - $30 to $60. Premium filters for the 6.4L cost a bit more.
- MAF sensor cleaning - $10 to $15.
- MAF sensor replacement - $200 to $400 with labor.
- O2 sensor replacement - $250 to $450 for parts and labor.
- Fuel injector replacement - $400 to $900. The dual-injection system means higher parts costs.
- Fuel pressure regulator replacement - $300 to $600 for parts and labor.
Prevention Tips
Use Top Tier premium fuel as recommended for the 6.4L HEMI. Replace the air filter at recommended intervals. Have the fuel system inspected during scheduled maintenance. The dual-injection system benefits from periodic fuel system cleaning to prevent carbon buildup. Monitor fuel economy trends and address any changes promptly to avoid expensive downstream repairs like catalytic converter replacement, which can exceed $2,000 on the Grand Wagoneer.