how to diagnose P0171 code on Honda Pilot Third Generation (2016-present)

Solution

1. Preparation

• Gather tools and parts needed for repair.
• Disconnect the battery to ensure safety while working on electrical components.
• Allow the engine to cool down if it has been running.

2. Inspect and Repair Air Intake System

• Check for Vacuum Leaks:
  • Visually inspect vacuum hoses for cracks or disconnections.
  • Use a smoke machine or carburetor cleaner to detect leaks.
• Repair or Replace Damaged Components:
  • Replace any damaged hoses or gaskets found during inspection.

3. Fuel System Inspection and Repair

• Check Fuel Pressure:
  • Connect a fuel pressure gauge to the fuel rail.
  • Compare the reading to manufacturer's specifications (typically 40-50 psi).
• Replace Fuel Filter:
  • If fuel pressure is low, replace the fuel filter.
  • Follow manufacturer guidelines for the replacement procedure.
• Test Fuel Injectors:
  • Use a multimeter to check for proper resistance.
  • Replace any faulty injectors.

4. Mass Air Flow Sensor Maintenance

• Clean the MAF Sensor:
  • Remove the MAF sensor from the intake.
  • Use MAF sensor cleaner to clean the sensor wire.
• Reinstall the MAF Sensor:
  • Ensure it is securely fastened and reconnected.

5. Oxygen Sensor Evaluation

• Test Oxygen Sensor:
  • Use a multimeter to check the voltage output of the O2 sensor.
  • Replace the sensor if readings are out of specification (typically fluctuates between 0.1 to 0.9 volts).

6. Reassemble and Clear Codes

• Reconnect the battery.
• Clear the P0171 code using the OBD-II scanner.
• Start the engine and monitor for any reoccurrence of the check engine light.