how to fix P0171 code on Toyota RAV4 Fifth Generation (2019-present)?

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the battery to ensure safety while working on electrical components.
• Raise the vehicle and secure it on jack stands if necessary.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum hoses for cracks or disconnections.
  2. Use a smoke machine or carburetor cleaner to detect leaks by spraying around the intake manifold and hoses.
  3. Replace any damaged hoses or re-secure loose connections.

3. Clean or Replace MAF Sensor

• Sub-steps:
  1. Locate the MAF sensor in the air intake system.
  2. Disconnect the electrical connector and remove the sensor from the housing.
  3. Clean the MAF sensor using MAF sensor cleaner; do not touch the sensor elements.
  4. Reinstall the sensor and reconnect the electrical connector.

4. Check Fuel System

• Sub-steps:
  1. Use a fuel pressure gauge to check the fuel pump pressure against manufacturer specifications (typically around 30-40 psi).
  2. Replace the fuel filter if it is clogged or has not been changed in accordance with the maintenance schedule.
  3. If pressure is low, test the fuel pump relay and wiring before replacing the pump.

5. Inspect Fuel Injectors

• Sub-steps:
  1. Remove the fuel injectors from the fuel rail.
  2. Inspect for dirt or debris; clean or replace injectors as necessary.
  3. Reinstall the injectors, ensuring a secure fit.

6. Verify O2 Sensor Function

• Sub-steps:
  1. Use a multimeter to check the voltage output of the upstream O2 sensor.
  2. Replace the sensor if it shows a constant voltage or is out of specification.