how to fix P0171 in Toyota RAV4 XA40 (2013-2018)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal.
• Allow the engine to cool down.

2. Inspect for Vacuum Leaks

• Tools Required: Vacuum gauge, flashlight
• Visually inspect all vacuum hoses for cracks or disconnections.
• Use a vacuum gauge to check for proper vacuum levels; compare with specifications.
• If leaks are found, replace damaged hoses or gaskets.

3. Clean or Replace MAF Sensor

• Tools Required: MAF sensor cleaner, screwdriver
• Locate the MAF sensor, typically found between the air filter and throttle body.
• Disconnect the electrical connector and remove the sensor.
• Clean the MAF sensor using MAF sensor cleaner; do not touch the sensor elements.
• Reinstall the MAF sensor and reconnect the electrical connector. If the MAF sensor is faulty, replace it.

4. Test Fuel Pressure

• Tools Required: Fuel pressure gauge, hose clamps
• Locate the fuel rail and connect the fuel pressure gauge.
• Turn the ignition to the "ON" position (do not start the engine) to check the pressure.
• Compare the reading to the manufacturer’s specifications; if low, check the fuel pump and filter.

5. Inspect Fuel Injectors

• Tools Required: Multimeter, injector cleaner (if needed)
• Check each fuel injector's resistance with a multimeter to ensure they are within specifications.
• If clogged, use a fuel injector cleaner or replace injectors as necessary.

6. Replace Oxygen Sensor (if necessary)

• Tools Required: Oxygen sensor socket, wrench
• Locate the upstream oxygen sensor (usually before the catalytic converter).
• Disconnect the electrical connector and remove the sensor.
• Install the new oxygen sensor and reconnect the electrical connector.