how to fix P0171 code on Honda Civic 9th Generation (2012-2015)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to prevent electrical shock.
• Allow the engine to cool down before starting work.

2. Inspect and Repair Vacuum Leaks

• Tools Required: Vacuum gauge, hose clamps, spray bottle with soapy water
• Inspect all vacuum hoses for cracks or disconnections.
• Use the vacuum gauge to measure the vacuum levels; if low, locate the source of the leak.
• Apply soapy water to suspect areas; bubbles will indicate leaks.
• Replace any damaged hoses or fittings and ensure all connections are secure.

3. Clean or Replace MAF Sensor

• Tools Required: MAF sensor cleaner, screwdriver
• Locate the MAF sensor in the air intake duct.
• Disconnect the electrical connector and remove the sensor from the duct.
• Spray MAF sensor cleaner on the sensor element and allow it to dry.
• Reinstall the MAF sensor and reconnect the electrical connector.

4. Test and Repair Fuel System

• Tools Required: Fuel pressure gauge, fuel injector cleaner
• Connect the fuel pressure gauge to the fuel rail and turn the ignition on (do not start the engine) to check fuel pressure.
• If the pressure is below specifications, inspect the fuel pump and replace it if necessary.
• If the pressure is adequate, use a fuel injector cleaner in the fuel tank to clean any clogged injectors.

5. Inspect Oxygen Sensor

• Tools Required: O2 sensor socket, multimeter
• Locate the upstream oxygen sensor and disconnect the electrical connector.
• Use the O2 sensor socket to remove the sensor from the exhaust system.
• Test the sensor's resistance with a multimeter; replace if it is out of specification.
• Reinstall the new sensor and reconnect the electrical connector.