why does my Honda Accord have a check engine light with code P0171

Solution

1. Preparation

• Gather tools and materials required for the repair.
• Ensure the vehicle is parked on a level surface with the engine off.
• Disconnect the battery to prevent electrical shorts.

2. Inspect Air Intake and MAF Sensor

• Remove the air intake duct connected to the throttle body.
• Inspect the air filter and replace it if necessary.
• Clean the MAF sensor using MAF cleaner (do not use regular cleaners).
• Reinstall the air intake duct securely.

3. Check for Vacuum Leaks

• Visually inspect all vacuum hoses attached to the intake manifold.
• Replace any damaged or cracked hoses.
• Use a smoke machine or carburetor cleaner to detect leaks around the intake manifold and vacuum hoses.

4. Test Fuel System

• Connect a fuel pressure gauge to the fuel rail.
• Turn the ignition to the "ON" position (do not start the engine) and check the fuel pressure; it should meet the manufacturer's specifications (usually between 30-50 psi).
• If pressure is low, check the fuel pump and fuel filter for faults; replace if necessary.

5. Inspect Fuel Injectors

• Remove the fuel injectors from the fuel rail.
• Clean or replace injectors if they are clogged or not functioning correctly.
• Reinstall injectors and ensure they are securely connected.