how to fix P0171 lean code in Toyota RAV4 XA50 (2019-2024)

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, vacuum gauge, fuel pressure gauge, basic hand tools (sockets and wrenches)
• Disconnect the negative battery terminal to prevent any electrical shorts.

2. Inspect Air Intake System

1. Visually check all vacuum hoses leading to the intake manifold for cracks or disconnections.
2. Inspect the intake manifold gasket for signs of wear or leaks.
3. Use a vacuum gauge to measure intake manifold vacuum; low readings may indicate a leak.

3. Test MAF Sensor

1. Disconnect the MAF sensor electrical connector.
2. Use a multimeter to measure the output voltage while gently revving the engine; it should vary according to engine load.
3. If readings are out of specification, replace the MAF sensor.

4. Check Fuel Pressure

1. Locate the fuel pressure test port on the fuel rail.
2. Attach the fuel pressure gauge and turn the ignition to the "ON" position without starting the engine.
3. Check that the fuel pressure meets manufacturer specifications (typically 30-50 psi for most RAV4s); replace the fuel pump or filter if pressure is low.

5. Inspect Fuel Injectors

1. Remove the engine cover to access the fuel injectors.
2. Check for any leaks or cracks around the injectors.
3. Use a noid light to test the injector pulse while the engine is cranking, ensuring they are firing correctly. Replace any faulty injectors.

6. Examine Oxygen Sensors

1. Use the OBD-II scanner to monitor live data from the upstream oxygen sensor.
2. Check for any abnormal readings or slow response times.
3. Replace the oxygen sensor if it is not within specifications.