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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool before starting work.

2. Inspect and Repair Vacuum Leaks

• Tools Required: Vacuum gauge, hose clamps, screwdriver
• Inspect all vacuum hoses for cracks or disconnections.
• Use a vacuum gauge to test the intake manifold vacuum. If low, locate the leak.
• Replace any damaged hoses or reattach disconnected hoses.

3. Clean or Replace Mass Air Flow Sensor

• Tools Required: MAF sensor cleaner, screwdriver
• Disconnect the MAF sensor connector and remove it from the intake.
• Clean the MAF sensor with MAF sensor cleaner and let it dry completely.
• If heavily contaminated or damaged, replace the MAF sensor with a new one.

4. Test and Repair Fuel System

• Tools Required: Fuel pressure gauge
• Connect the fuel pressure gauge to the fuel rail test port.
• Turn the ignition to the "ON" position without starting the engine and check for proper fuel pressure (usually around 40-50 psi).
• If the pressure is low, check the fuel pump operation and replace the fuel filter if necessary.
• If the fuel pump is faulty, replace it.

5. Clean Throttle Body

• Tools Required: Throttle body cleaner, rag, screwdriver
• Remove the air intake duct connected to the throttle body.
• Spray throttle body cleaner on a rag and wipe the throttle body interior and the throttle plate until clean.
• Reassemble the air intake duct securely.

6. Replace Faulty Oxygen Sensor

• Tools Required: O2 sensor socket, wrench
• Locate the upstream O2 sensor in the exhaust manifold.
• Disconnect the electrical connector and unscrew the sensor using an O2 sensor socket.
• Install the new O2 sensor, ensuring it is torqued to manufacturer specifications (usually around 30 lb-ft).
• Reconnect the electrical connector.