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

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the negative battery terminal to avoid electrical shorts.
• Allow the engine to cool completely before starting work.

2. Inspect and Repair Air Intake System

• Inspect for Leaks:
  • Visually inspect the intake manifold and all vacuum hoses for cracks or disconnections.
  • Use a smoke machine to identify any hidden leaks.
• Repair:
  • Replace any damaged hoses or gaskets found during inspection.
  • Re-secure any loose connections.

3. Clean or Replace MAF Sensor

• Remove MAF Sensor:
  • Disconnect the electrical connector.
  • Unbolt and remove the MAF sensor from the air intake.
• Clean:
  • Use MAF sensor cleaner to clean the sensor elements gently. Allow it to dry.
• Replace:
  • If cleaning does not resolve the issue, replace the MAF sensor with a new one.

4. Inspect Fuel System

• Check Fuel Pressure:
  • Connect a fuel pressure gauge to the fuel rail.
  • Turn the ignition to the "ON" position (do not start) and check the fuel pressure against specifications.
• Replace Components:
  • If pressure is low, inspect and replace the fuel pump or filter as necessary.
  • Inspect injectors for clogs, and clean or replace as needed.

5. Check and Replace ECT Sensor

• Locate and Remove ECT Sensor:
  • Find the ECT sensor, usually located near the thermostat housing.
  • Unplug the electrical connector and unscrew the sensor.
• Replace:
  • Install a new ECT sensor and reconnect the electrical connector.