how to fix P0171 lean code in Toyota Camry Seventh Generation (2012-2017)

Solution

1. Preparation

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

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  • Visually inspect all vacuum hoses connected to the intake manifold for cracks or disconnections.
  • Use a smoke machine or propane torch (unlit) to detect vacuum leaks.
  • Replace any damaged hoses and reseal the intake manifold gasket if necessary.

3. Test and Clean MAF Sensor

• Sub-steps:
  • Locate the MAF sensor in the air intake duct.
  • Disconnect the electrical connector and remove the sensor from the duct.
  • Clean the MAF sensor using MAF cleaner spray (do not use other cleaners).
  • Reinstall the MAF sensor and reconnect the electrical connector.

4. Check Fuel Pressure

• Sub-steps:
  • Connect a fuel pressure gauge to the fuel rail.
  • Turn the ignition to the "ON" position without starting the engine and check the fuel pressure reading.
  • Compare the reading to the manufacturer's specifications (typically around 40-50 psi for most Toyota models).
  • If the pressure is low, inspect the fuel pump and filter for blockages or failures.

5. Inspect and Replace Fuel Injectors (if necessary)

• Sub-steps:
  • Remove the fuel rail and injectors.
  • Inspect the injectors for clogs and proper operation.
  • Clean or replace faulty injectors as needed and reinstall them with new O-rings.