how to fix a P0171 code in Honda Civic 10th Generation (2016-2021)

Solution

1. Preparation

• Gather tools and parts required.
• Disconnect the negative battery terminal to ensure safety.
• Allow the engine to cool before starting work.

2. Inspect and Repair Vacuum Leaks

• Tools Required: Vacuum gauge, hose clamps, scanner
• Check for any disconnected or cracked vacuum hoses.
• Use a vacuum gauge to measure intake manifold pressure. If it reads lower than expected, pinpoint the leak using a smoke machine or soapy water.
• Replace any damaged hoses or reattach loose connections.

3. Clean or Replace Mass Airflow Sensor

• Tools Required: Torx screwdriver, MAF cleaner
• Locate the MAF sensor in the air intake duct.
• Remove the MAF sensor using a Torx screwdriver.
• Clean the sensor elements carefully with MAF cleaner, avoiding physical contact with the sensor.
• If cleaning does not resolve issues, replace the MAF sensor.

4. Check Fuel System Pressure

• Tools Required: Fuel pressure gauge
• Locate the fuel rail pressure test port.
• Connect the fuel pressure gauge and turn the ignition to the "ON" position without starting the engine.
• Check if the fuel pressure is within the specifications (usually around 40-50 psi for most Honda models).
• If pressure is low, inspect the fuel pump and fuel filter for blockages or failure.

5. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench
• Locate the upstream oxygen sensor (pre-catalytic converter).
• Remove the sensor using an O2 sensor socket.
• Inspect the sensor for damage or contamination.
• Replace with a new oxygen sensor if necessary.