what does it mean if my Toyota RAV4 XA40 (2013-2018) shows a P0171 code?

Solution

1. Preparation

• Gather tools: OBD-II scanner, multimeter, fuel pressure gauge, basic hand tools, and safety gear (gloves and goggles).
• Disconnect the battery before starting work on electrical systems.

2. Inspect and Repair Air Intake System

• 1.1 Visually inspect all vacuum hoses for cracks or disconnections.
• 1.2 Replace any damaged hoses or reattach any loose connections.
• 1.3 Check the intake manifold gasket for leaks and replace if necessary.

3. Clean or Replace MAF Sensor

• 2.1 Disconnect the MAF sensor electrical connector.
• 2.2 Remove the MAF sensor from the air intake duct.
• 2.3 Clean the sensor using MAF cleaner spray. Do not touch the sensor element.
• 2.4 If cleaning does not resolve the issue, replace the MAF sensor with a new unit.

4. Test Fuel System

• 3.1 Connect the fuel pressure gauge to the fuel rail.
• 3.2 Turn the ignition to the "ON" position without starting the engine to check fuel pressure.
• 3.3 Compare the reading with the manufacturer’s specifications; if low, inspect the fuel pump and fuel filter.
• 3.4 Replace the fuel pump or filter as necessary.

5. Inspect Oxygen Sensors

• 4.1 Check the wiring and connectors of the upstream oxygen sensor for signs of damage.
• 4.2 Test the sensor’s voltage output using a multimeter while the engine is running.
• 4.3 Replace the oxygen sensor if it shows no response or incorrect values.