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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool if it was recently running.

2. Inspect Air Intake System

• Tools Required: Screwdriver set, flashlight
• Sub-steps:
  1. Visually inspect all vacuum hoses connected to the intake manifold for cracks or disconnections.
  2. Remove the air intake duct and check for leaks at the throttle body.
  3. Inspect the intake manifold gasket for signs of wear or damage.
  4. Replace any damaged hoses or gaskets as necessary.

3. Check MAF Sensor

• Tools Required: MAF sensor cleaner
• Sub-steps:
  1. Locate the MAF sensor in the air intake system.
  2. Disconnect the electrical connector and remove the MAF sensor.
  3. Clean the sensor using MAF sensor cleaner to remove any dirt or buildup.
  4. Reinstall the MAF sensor and reconnect the electrical connector.

4. Inspect Fuel System

• Tools Required: Fuel pressure gauge
• Sub-steps:
  1. Connect the fuel pressure gauge to the fuel rail.
  2. Turn the ignition on (without starting the engine) and check the fuel pressure against manufacturer specifications.
  3. If pressure is low, inspect the fuel pump and fuel filter for proper operation.
  4. Replace the fuel filter if necessary and consider replacing the fuel pump if it fails to maintain proper pressure.

5. Examine Oxygen Sensors

• Tools Required: OBD-II scanner, multimeter
• Sub-steps:
  1. Use an OBD-II scanner to check the voltage output of the upstream oxygen sensor.
  2. If the readings are inconsistent or outside of the normal range (0.1-0.9V), consider replacing the sensor.
  3. Follow the manufacturer's specifications for installation and torque settings during replacement.

6. Clear Codes and Test

• Tools Required: OBD-II scanner
• Sub-steps:
  1. Clear the P0171 code using the OBD-II scanner.
  2. Start the engine and allow it to reach operating temperature.
  3. Monitor the engine operation for any warning lights or abnormal behavior.