how to fix P0171 code on my Toyota RAV4 Fourth Generation (2013-2018)?

Solution

1. Preparation

• Gather tools and ensure safety equipment is available.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Inspect all vacuum lines connected to the intake manifold for cracks or disconnections.
  2. If leaks are found, replace the damaged hoses or reconnect loose fittings.
• Tools Required: Visual inspection tools, vacuum gauge.

3. Clean or Replace MAF Sensor

• Sub-steps:
  1. Disconnect the MAF sensor electrical connector.
  2. Remove the MAF sensor from the air intake.
  3. Clean the sensor with MAF cleaner; do not touch the sensor element.
  4. If cleaning does not resolve the issue, replace the MAF sensor with a new one.
• Tools Required: Screwdriver set, MAF cleaner.

4. Check Fuel System

• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail.
  2. Turn the ignition to the "ON" position (do not start the engine) and check the fuel pressure reading against manufacturer specifications.
  3. If the pressure is low, inspect the fuel pump, filter, and relay for faults; replace as necessary.
• Tools Required: Fuel pressure gauge, basic hand tools.

5. Examine Oxygen Sensors

• Sub-steps:
  1. Access the upstream oxygen sensor; disconnect it.
  2. Use a multimeter to check the voltage output of the sensor while the engine is running.
  3. Replace the oxygen sensor if the output is outside of specifications.
• Tools Required: Multimeter, oxygen sensor socket.