how to fix P0171 code on my Toyota RAV4 XA40 (2013-2018)

Solution

1. Preparation

• Gather tools and parts needed.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool completely.

2. Inspect and Repair Vacuum Leaks

• Tools Required: Vacuum gauge, socket set, torque wrench.
• Use a vacuum gauge to check for leaks; a reading outside of normal parameters indicates a leak.
• Visually inspect all hoses and connections; replace any cracked or damaged hoses.
• Re-torque intake manifold bolts to the manufacturer's specifications if necessary.

3. Clean or Replace MAF Sensor

• Tools Required: MAF cleaner, screwdriver.
• Remove the MAF sensor from the air intake duct.
• Spray the MAF cleaner onto the sensor elements; do not touch them with any tools or fingers.
• Allow the sensor to dry completely before reinstalling it.

4. Test and Repair Fuel System

• Tools Required: Fuel pressure gauge, socket set.
• Connect the fuel pressure gauge to the fuel rail; turn the ignition on (do not start the engine) to check pressure.
• If pressure is low, check the fuel pump and filter for functionality; replace if necessary.
• If fuel injectors are clogged, use a fuel injector cleaner or remove and clean them manually.

5. Verify Engine Coolant Temperature Sensor

• Tools Required: Multimeter.
• Disconnect the coolant temperature sensor and measure its resistance with a multimeter.
• Compare the resistance to the specifications in the service manual; replace the sensor if it is out of range.