how to fix P0171 lean code on my Toyota RAV4 Fourth Generation (2013-2018)?

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery before starting work to avoid electrical shorts.

2. Inspect and Repair Vacuum Leaks

• Sub-step 1: Visually inspect all vacuum lines for cracks or disconnections.
• Sub-step 2: Use a smoke machine or carburetor cleaner to check for leaks; listen for hissing sounds.
• Sub-step 3: Replace any damaged hoses or gaskets found during the inspection.

3. Clean or Replace MAF Sensor

• Sub-step 1: Remove the MAF sensor from the air intake duct using a screwdriver.
• Sub-step 2: Clean the MAF sensor with MAF cleaner spray; allow it to dry completely.
• Sub-step 3: If the sensor is damaged, replace it with a new one.

4. Check and Repair Fuel System

• Sub-step 1: Check the fuel pressure using a fuel pressure gauge; ensure it matches the manufacturer’s specifications (usually around 30-40 PSI).
• Sub-step 2: If pressure is low, inspect and replace the fuel filter or fuel pump as necessary.
• Sub-step 3: Inspect fuel injectors for clogs or leaks; clean or replace them if needed.

5. Inspect Oxygen Sensors

• Sub-step 1: Use a multimeter to test the voltage output of the oxygen sensors; it should fluctuate between 0.1 to 0.9 volts.
• Sub-step 2: Replace any faulty oxygen sensors.

6. Reassemble and Reconnect Battery

• Sub-step 1: After repairs, reassemble any components that were removed.
• Sub-step 2: Reconnect the battery and clear the OBD-II codes using the scanner.