how to fix P0171 code on my Toyota RAV4 XA40 (2013-2018)

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the negative battery terminal to prevent any electrical shorts.
• Allow the engine to cool before beginning work.

2. Inspect and Repair Air Intake System

• Tools Required: Socket set, screwdrivers, vacuum gauge
• Sub-steps:
  1. Remove the engine cover (if applicable) using a socket set.
  2. Inspect all vacuum hoses connected to the intake manifold for cracks or disconnections.
  3. Replace any damaged hoses with OEM parts.
  4. Check the intake manifold gasket for leaks; replace if necessary.

3. Clean or Replace MAF Sensor

• Tools Required: MAF sensor cleaner, screwdriver
• Sub-steps:
  1. Locate the MAF sensor between the air filter and the throttle body.
  2. Disconnect the electrical connector from the MAF sensor.
  3. Remove the sensor using a screwdriver.
  4. Clean the sensor using MAF sensor cleaner; do not touch the sensor element.
  5. Reinstall the sensor and reconnect the electrical connector.

4. Test Fuel Pressure

• Tools Required: Fuel pressure gauge
• Sub-steps:
  1. Locate the fuel rail and connect the fuel pressure gauge.
  2. Turn the ignition to the "On" position without starting the engine to build pressure.
  3. Check the pressure reading against the manufacturer's specifications (typically 35-50 psi for RAV4).
  4. If pressure is low, inspect the fuel pump and fuel filter; replace if necessary.

5. Inspect Fuel Injectors

• Tools Required: Multimeter, cleaning kit
• Sub-steps:
  1. Locate the fuel injectors on the engine.
  2. Use a multimeter to check the resistance of each injector; compare to specifications.
  3. If injectors are faulty, replace them with OEM parts.
  4. Clean the injectors using a cleaning kit if they are clogged.