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

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the battery to ensure safety.
• Allow the engine to cool if it has been running.

2. Inspect and Repair Vacuum Leaks

• Check all vacuum hoses connected to the intake manifold for cracks or disconnections.
• If any are damaged, replace them with new hoses.
• Inspect the intake manifold gasket and replace if it is worn or leaking.

3. Clean or Replace MAF Sensor

• Locate the MAF sensor in the air intake duct.
• Disconnect the electrical connector and remove the sensor using a Torx or socket wrench.
• Clean the MAF sensor with MAF cleaner spray; do not touch the sensor element.
• Reinstall the sensor securely or replace it if damaged.

4. Verify Fuel System Performance

• Connect a fuel pressure gauge to the fuel rail.
• Turn the ignition to the "ON" position (do not start) and read the fuel pressure.
• Compare the reading to manufacturer specifications; it should typically be between 50-60 psi.
• If pressure is low, check the fuel pump and filter for issues, replacing as necessary.

5. Inspect Oxygen Sensors

• Locate the upstream oxygen sensor (pre-cat) and inspect the wiring and connector for damage.
• Use a multimeter to test the sensor’s voltage output. A healthy sensor should fluctuate between 0.1V and 0.9V.
• Replace the oxygen sensor if it is faulty.