how to fix P0171 code in Toyota Corolla E140 (2006-2013)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Repair Air Intake System

• Tools Required: Socket set, pliers, flashlight
• Sub-steps:
  1. Visually inspect all vacuum hoses and connections for cracks, breaks, or loose fittings.
  2. Tighten any loose clamps on the air intake.
  3. Replace any damaged hoses with OEM or high-quality aftermarket parts.

3. Clean or Replace MAF Sensor

• Tools Required: MAF sensor cleaner, screwdriver
• Sub-steps:
  1. Remove the MAF sensor from the air intake duct using a screwdriver.
  2. Spray the MAF sensor with a dedicated MAF sensor cleaner and let it dry completely.
  3. Reinstall the MAF sensor, ensuring it is securely fastened.

4. Check and Adjust Fuel System Pressure

• Tools Required: Fuel pressure gauge
• Sub-steps:
  1. Connect the fuel pressure gauge to the fuel rail service port.
  2. Turn the ignition to the ON position (do not start the engine) and read the pressure. Refer to the service manual for the correct pressure range.
  3. If the pressure is low, check the fuel pump operation and replace if necessary.

5. Test and Clean Fuel Injectors

• Tools Required: Fuel injector cleaning kit, multimeter
• Sub-steps:
  1. Disconnect the fuel injector connectors.
  2. Use a multimeter to check for proper voltage at the injector connectors.
  3. If voltage is present, use a fuel injector cleaning kit to clean the injectors; if not, check wiring and connectors for issues.

6. Inspect and Test Oxygen Sensors

• Tools Required: Multimeter
• Sub-steps:
  1. Locate the upstream oxygen sensor and disconnect the electrical connector.
  2. Using a multimeter, test the voltage output of the sensor while the engine is running. It should fluctuate between 0.1 to 0.9 volts.
  3. If the sensor is out of range, replace it with an OEM part.