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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative battery terminal to prevent accidental electrical shorts.

2. Inspect and Repair Vacuum Leaks

• Tools Required: Vacuum gauge, hose clamps, screwdriver.
• Inspect all vacuum hoses for cracks or disconnections. Replace any damaged hoses.
• Use a vacuum gauge to check the intake manifold for leaks. Tighten or repair as necessary.

3. Clean or Replace MAF Sensor

• Tools Required: MAF sensor cleaner, screwdriver.
• Remove the MAF sensor from the air intake duct.
• Spray MAF sensor cleaner onto the sensor elements and allow it to dry completely before reinstalling.
• If the sensor is damaged, replace it with a new one.

4. Check and Repair Fuel System

• Tools Required: Fuel pressure gauge, wrench set.
• Connect a fuel pressure gauge to the fuel rail and check for proper fuel pressure according to manufacturer specifications (usually around 40-50 psi).
• If the pressure is low, inspect and replace the fuel filter and check the fuel pump for functionality.

5. Inspect Oxygen Sensors

• Tools Required: O2 sensor socket or wrench, multimeter.
• Remove the upstream oxygen sensor and inspect it for carbon buildup or damage. Clean or replace as necessary.
• Test the sensor’s voltage with a multimeter to ensure it varies correctly (0.1 to 0.9 volts).

6. Replace Engine Coolant Temperature Sensor (if necessary)

• Tools Required: Socket set, coolant.
• Locate the ECT sensor on the engine, disconnect the electrical connector, and remove the sensor.
• Install the new ECT sensor and refill any lost coolant.