how to fix P0171 code in my Toyota Camry Eighth Generation (2018-present)

Solution

1. Preparation

• Gather tools and parts.
• Ensure the vehicle is parked on a level surface with the engine off.
• Disconnect the negative battery terminal.

2. Inspect Air Intake System

• Tools Required: Flathead screwdriver, pliers
• Remove the air intake duct and visually inspect for cracks or loose connections.
• Check all vacuum hoses connected to the intake manifold for damages. Replace any damaged hoses.
• Ensure the throttle body is clean and free of carbon buildup.

3. Clean or Replace MAF Sensor

• Tools Required: MAF cleaner spray, torx or socket set
• Disconnect the MAF sensor electrical connector.
• Remove the MAF sensor from the air intake assembly.
• Spray MAF cleaner onto the sensor and allow it to dry. If damaged, replace the sensor.
• Reinstall the MAF sensor and reconnect the electrical connector.

4. Inspect Fuel System

• Tools Required: Fuel pressure gauge, socket set
• Connect the fuel pressure gauge to the fuel rail test port.
• Turn the ignition key to the "On" position (do not start the engine) to check fuel pressure. It should match the specifications in the repair manual (typically around 40-50 psi).
• If pressure is low, inspect the fuel pump and replace the fuel filter if necessary.

5. Test Oxygen Sensor

• Tools Required: Multimeter
• Locate the upstream oxygen sensor (pre-catalytic converter).
• Use a multimeter to check the voltage output of the sensor while the engine is running. It should fluctuate between 0.1 to 0.9 volts.
• If the output is steady or out of range, replace the oxygen sensor.

6. Clear Codes and Test Drive

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0171 code.
• Test drive the vehicle to ensure the issue is resolved and check for any reoccurrence of the code.