how do I fix the P0171 code on my Honda Civic 10th Generation (2016-2021)

Solution

1. Preparation

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

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum hoses for cracks, wear, or disconnections.
  2. Use a smoke machine or carb cleaner to identify leaks while the engine is running.
  3. Replace any damaged hoses or gaskets as necessary.

3. Clean or Replace MAF Sensor

• Tools Required: MAF sensor cleaner, screwdriver
• Sub-steps:
  1. Locate the MAF sensor; it is typically found between the air filter and the throttle body.
  2. Disconnect the MAF sensor wiring harness.
  3. Remove the MAF sensor using a screwdriver.
  4. Clean the sensor element with MAF sensor cleaner; do not touch the sensor element with fingers.
  5. Reinstall the MAF sensor and reconnect the wiring harness. If damaged, replace it.

4. Check and Repair Fuel System

• Tools Required: Fuel pressure gauge
• Sub-steps:
  1. Connect the fuel pressure gauge to the fuel rail.
  2. Turn the ignition on without starting the engine to check the fuel pressure reading.
  3. Compare the reading with manufacturer specifications (usually around 40-50 psi for most Hondas).
  4. If pressure is low, check the fuel pump and fuel filter for issues and replace as necessary.

5. Verify ECT Sensor Operation

• Sub-steps:
  1. Locate the ECT sensor, usually found near the thermostat housing.
  2. Disconnect the wiring harness from the ECT sensor.
  3. Use a multimeter to check the resistance of the sensor; compare it with specifications at various temperatures. Replace if out of range.