how to fix P0171 code in Toyota Corolla E210 (2019-2024)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative terminal of the battery.
• Allow the engine to cool down.

2. Inspect and Repair Air Intake System

• Tools Required: Socket set, screwdrivers, vacuum gauge.
• Sub-steps:
  1. Visually inspect all air intake hoses for cracks or disconnections.
  2. Use a vacuum gauge to test for vacuum leaks in the intake manifold.
  3. If any leaks are found, replace the damaged hoses or components.

3. Clean or Replace MAF Sensor

• Tools Required: MAF cleaner, soft cloth.
• Sub-steps:
  1. Locate the MAF sensor on the air intake duct.
  2. Disconnect the electrical connector and remove the sensor carefully.
  3. Spray MAF cleaner on the sensor element and allow it to dry completely.
  4. Reinstall the sensor and reconnect the electrical connector.

4. Inspect Fuel System

• Tools Required: Fuel pressure gauge, socket set.
• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail.
  2. Turn the ignition to the ON position (without starting) and check the pressure reading.
  3. If the pressure is below specifications, inspect the fuel pump and replace the fuel filter if necessary.

5. Oxygen Sensor Testing

• Tools Required: Multimeter.
• Sub-steps:
  1. Locate the upstream oxygen sensor (pre-catalytic converter).
  2. Disconnect the sensor and use a multimeter to check the voltage output while the engine is running.
  3. If the voltage is not fluctuating between 0.1V to 0.9V, consider replacing the oxygen sensor.