Understanding P0174 on the 2023 Honda Pilot
A P0174 code on the 2023 Honda Pilot means the powertrain control module has detected a lean air-fuel mixture on Bank 2. The 2023 Pilot features an all-new design with a 3.5-liter V6 engine producing 285 hp and 262 lb-ft of torque, paired with a 10-speed automatic transmission. As a V6, the engine has two cylinder banks, and P0174 correctly identifies that Bank 2 (rear bank) is running lean.
A lean mixture means the air-fuel ratio has shifted toward too much air or too little fuel on the rear bank of cylinders. This needs attention to prevent engine damage from elevated combustion temperatures.
Symptoms
- Check engine light on
- Rough or uneven idle
- Hesitation during acceleration
- Reduced power
- Engine running hotter than normal
- Potential misfires on rear bank cylinders
Common Causes
- Vacuum Leak at Bank 2 - The rear bank of the V6 is more difficult to inspect, and leaking gaskets or hoses near the firewall side of the engine can admit unmetered air.
- Contaminated MAF Sensor - A dirty mass airflow sensor causes the ECM to underestimate total airflow and deliver insufficient fuel.
- Restricted Fuel Injector on Bank 2 - A partially clogged injector on one of the rear bank cylinders limits fuel delivery to that cylinder.
- Bank 2 Upstream O2 Sensor Issue - A sluggish or biased oxygen sensor on Bank 2 causes incorrect fuel trim adjustments on that bank.
Diagnostic Steps
- Read all codes - Check for P0171 alongside P0174. Both codes suggest a common cause.
- Inspect for vacuum leaks - Focus on the rear bank area. Smoke testing is recommended.
- Clean the MAF sensor - Quick and inexpensive first step.
- Compare bank fuel trims - Use a scan tool to compare Bank 1 and Bank 2 STFT and LTFT.
- Test fuel injectors - Run an injector balance test to identify restricted injectors.
Repair Costs
- Vacuum hose repair - $5 to $30, plus $80 to $160 labor for rear bank access.
- Intake manifold gasket - $40 to $95, plus $260 to $470 labor.
- MAF sensor cleaning - $10 to $25.
- MAF sensor replacement - $95 to $210, plus $50 to $100 labor.
- Fuel injector replacement - $65 to $150 per injector, plus $220 to $420 labor.
- O2 sensor replacement - $75 to $180, plus $80 to $170 labor.
DIY Feasibility
MAF sensor work and front-accessible hose checks are easy DIY tasks. Rear bank work on the new Pilot V6 requires patience due to limited space. O2 sensor replacement is manageable with proper tools. Intake gasket and fuel injector work at the rear are best handled by a shop.
Prevention Tips
- Follow Honda's maintenance schedule rigorously on this new platform
- Use top-tier gasoline
- Inspect vacuum connections during routine service
- Keep the air filter clean
- Address check engine lights promptly