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

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, multimeter, fuel pressure gauge, vacuum gauge, cleaning solvent.
• Ensure the vehicle is parked on a level surface and the engine is cool. Disconnect the negative battery terminal to avoid electrical shorts.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum hoses and connections for cracks or disconnections.
  2. Use a vacuum gauge to test for leaks; connect it to a vacuum source and observe the reading.
  3. If a leak is found, replace the damaged hoses or gaskets as necessary.

3. Clean or Replace MAF Sensor

• Sub-steps:
  1. Locate the MAF sensor in the air intake duct.
  2. Disconnect the electrical connector and remove the sensor using a socket set.
  3. Clean the MAF sensor with MAF cleaner spray. Allow it to dry completely.
  4. Reinstall the MAF sensor and reconnect the electrical connector.

4. Test Fuel System

• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail test port.
  2. Turn the ignition on (do not start the engine) and check the fuel pressure reading.
  3. Compare the reading to manufacturer specifications (usually around 40-50 psi for Honda Civic).
  4. If pressure is low, check the fuel pump and filter; replace if necessary.

5. Inspect and Repair Exhaust System

• Sub-steps:
  1. Inspect the exhaust system from the engine to the tailpipe for any visible cracks or holes.
  2. If leaks are found, repair or replace the affected sections of the exhaust.