how to troubleshoot a P0171 code on my Honda Civic 10th Generation (2016-2021)?

Solution

1. Preparation

• Gather required tools and parts.
• Disconnect the battery to ensure safety while working on electrical components.

2. Inspect and Repair Vacuum Leaks

• Tools Required: Vacuum gauge, hose clamps, screwdriver, and replacements for damaged hoses.
• Inspect all vacuum lines for cracks or disconnections.
• Use a vacuum gauge to test the intake manifold for any leaks.
• Replace any damaged hoses or gaskets found.

3. Check and Clean the Mass Airflow Sensor (MAF)

• Tools Required: MAF cleaner or isopropyl alcohol, soft brush.
• Disconnect the electrical connector from the MAF sensor.
• Remove the MAF sensor from the intake.
• Spray MAF cleaner on the sensor elements and let it dry completely before reinstallation.

4. Fuel System Inspection

• Tools Required: Fuel pressure gauge, fuel filter.
• Connect the fuel pressure gauge to the fuel rail and turn the ignition on (do not start the engine) to check for proper fuel pressure.
• If pressure is low, check the fuel pump and replace the fuel filter if it is clogged.
• Inspect fuel injectors for leaks or clogs and clean or replace them as necessary.

5. Inspect Oxygen Sensors

• Tools Required: O2 sensor socket, multimeter.
• Disconnect the upstream oxygen sensor and check its resistance with a multimeter to ensure it’s within specifications.
• If the sensor is faulty, replace it with a new one.

6. Throttle Body Cleaning

• Tools Required: Throttle body cleaner, soft cloth, and screwdriver.
• Remove the air intake duct from the throttle body.
• Spray throttle body cleaner on the throttle plate and inside the throttle body while moving the plate open and closed.
• Wipe clean with a soft cloth and reassemble.