how to fix P0171 code in my Toyota Tacoma N300 (2016-Present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect for Vacuum Leaks

• Tools Required: Vacuum gauge, smoke machine (optional)
• Steps:
  1. Visually inspect all vacuum hoses connected to the intake manifold for cracks or disconnections.
  2. Use a smoke machine to introduce smoke into the intake system; observe for any smoke escaping, indicating leaks.
  3. Repair or replace any damaged hoses or gaskets found during inspection.

3. Clean or Replace MAF Sensor

• Tools Required: MAF sensor cleaner
• Steps:
  1. Locate the MAF sensor in the air intake duct.
  2. Disconnect the electrical connector and unscrew the sensor from the duct.
  3. Clean the MAF sensor element using a suitable MAF cleaner.
  4. Allow the sensor to dry completely before reinstalling.
  5. Reconnect the electrical connector and secure the sensor back in place.

4. Check Fuel Pressure

• Tools Required: Fuel pressure gauge
• Steps:
  1. Connect the fuel pressure gauge to the fuel rail test port.
  2. Turn the ignition key to the "ON" position (do not start the engine) and check the pressure reading.
  3. Compare the reading to the manufacturer's specifications (typically around 50-60 psi for most Toyota models).
  4. If pressure is low, check the fuel pump operation and replace if necessary.

5. Inspect Oxygen Sensors

• Tools Required: Multimeter
• Steps:
  1. Locate the upstream oxygen sensor on the exhaust manifold or exhaust pipe.
  2. Disconnect the sensor’s electrical connector.
  3. Use a multimeter to check the sensor's voltage output; it should oscillate between 0.1 to 0.9 volts.
  4. If the readings are abnormal, replace the oxygen sensor with a new one.

6. Test Drive and Clear Codes

• After making repairs, reconnect the negative battery terminal.
• Start the engine and allow it to reach operating temperature.
• Take the vehicle for a test drive to ensure normal operation.
• Use the OBD-II scanner to clear the P0171 code and verify that it does not return.