how to fix P0171 code on my Toyota Camry Eighth Generation (2018-present)

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the battery to prevent electrical shocks.
• Ensure the engine is cool before starting work.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all hoses connected to the intake system for cracks or disconnections.
  2. Use a smoke machine or carburetor cleaner to identify leaks by spraying around suspected areas.
  3. Replace any faulty hoses or gaskets found during inspection.

3. Clean or Replace MAF Sensor

• Sub-steps:
  1. Locate the MAF sensor in the air intake system.
  2. Disconnect the electrical connector and unscrew the sensor from the housing.
  3. Clean the sensor carefully using MAF cleaner; do not touch the sensing element.
  4. If cleaning does not resolve the issue, replace the MAF sensor with a new unit.
  5. Reinstall the sensor and reconnect the electrical connector.

4. Check and Repair Fuel Delivery

• Sub-steps:
  1. Connect the fuel pressure gauge to the fuel rail's test port.
  2. Turn the ignition to the "ON" position (do not start the engine) and read the pressure.
  3. If pressure is below specifications (generally around 40-50 psi for most vehicles), inspect the fuel pump, filter, and lines.
  4. Replace any faulty components as needed.

5. Inspect Fuel Injectors

• Sub-steps:
  1. Remove the fuel rail with the injectors attached.
  2. Check for clogs in the injectors by performing a resistance test with a multimeter.
  3. Clean injectors using an ultrasonic cleaner or replace them if they are malfunctioning.
  4. Reinstall the fuel rail and ensure all connections are secure.

6. Test Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors.
  2. Use a multimeter to test the voltage output of the sensors while the engine is running.
  3. Replace any faulty sensors based on their voltage readings or if they show signs of physical damage.