P0171 Honda Pilot
System Too Lean (Bank 1) · Powertrain Code · High · Repair: Easy
What is P0171?
The engine is running lean on bank 1 — too much air or not enough fuel. Common causes include vacuum leaks, weak fuel pump, clogged fuel injectors, or a faulty MAF sensor.
When the Honda Pilot triggers code P0171 (system too lean (bank 1)), it typically points to an issue in the powertrain system. This is a high severity code, so address it promptly to avoid further damage or safety concerns. Below you'll find the most common causes, symptoms, and repair options specific to the Honda Pilot.
This repair is rated easy, meaning basic tools, no lift needed.
Diagnostic data on this page is compiled from publicly available repair resources and technical service bulletins. Always have a qualified mechanic confirm the diagnosis before authorizing repairs on your Honda Pilot.
Common Causes on Honda Pilot
- Intake manifold gasket leak on 1.5L turbo CR-V or 3.5L V6 Pilot causing lean condition
- PCV valve failure on 1.5L turbo CR-V creating vacuum leak and oil contamination
- MAF sensor contamination from fuel dilution oil mist on 1.5T CR-V (2017-2020)
- Cracked intake air tube between air filter and throttle body on 3.5L Pilot
- EVAP purge valve stuck open on CR-V allowing unmetered air into intake
Symptoms
- Rough or unstable idle speed
- Hesitation or stumble during acceleration
- Engine surging or hunting at idle
- Lean misfire under load causing jerking
- Poor acceleration response and reduced power
- Check engine light illuminated
Notes for Honda Pilot
The 2017-2020 CR-V 1.5T fuel dilution issue contributes to MAF contamination and lean codes.