how to fix P0171 and P0174 codes on my Toyota RAV4

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the vehicle's battery to ensure safety.
• Allow the engine to cool if it has been running.

2. Inspect and Repair Air Intake System

• Sub-steps:
  1. Remove the air intake duct to access the throttle body.
  2. Inspect the duct for cracks or loose connections.
  3. If defects are found, replace the air intake duct.
  4. Reinstall the duct securely and reconnect any clips or clamps.

3. Clean or Replace the Mass Air Flow Sensor

• Tools Required: MAF cleaner or isopropyl alcohol, soft cloth.
• Sub-steps:
  1. Disconnect the MAF sensor electrical connector.
  2. Remove the MAF sensor from the air intake.
  3. Spray the MAF sensor with MAF cleaner, avoiding touching the sensor elements.
  4. Allow it to dry completely before reinstalling.
  5. If cleaning does not resolve the issue, replace the MAF sensor.

4. Inspect and Repair Vacuum Hoses

• Sub-steps:
  1. Visually inspect all vacuum hoses for signs of wear, cracks, or disconnections.
  2. Replace any damaged hoses with OEM parts.
  3. Ensure all connections are secure and tight.

5. Test and Clean Fuel Injectors

• Tools Required: Fuel injector cleaning kit, multimeter.
• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail to check fuel pressure.
  2. If pressure is low, inspect the fuel pump and filter for issues.
  3. If injectors are clogged, use a fuel injector cleaning kit to clean them, following the manufacturer's instructions.

6. Reassemble and Reconnect

• Sub-steps:
  1. Reinstall any components removed during the inspection.
  2. Reconnect the battery.
  3. Start the engine and check for any leaks or abnormal sounds.