what does it mean if my Toyota Tacoma N300 (2016-Present) has a P0171 code

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the battery to ensure safety while working on electrical components.

2. Inspect and Repair Air Intake System

• Sub-steps:
  1. Visually inspect all air intake hoses for cracks or disconnections.
  2. Tighten any loose clamps and replace damaged hoses.
  3. Remove the intake manifold cover and inspect the gasket for leaks. Replace if necessary.

3. Fuel Pressure Check

• Sub-steps:
  1. Attach a fuel pressure gauge to the fuel rail test port.
  2. Turn the ignition key to the "ON" position (do not start) and check the fuel pressure reading.
  3. Compare the reading to manufacturer specifications; replace the fuel pump if pressure is low.

4. Clean or Replace MAF Sensor

• Sub-steps:
  1. Disconnect the MAF sensor wiring harness.
  2. Remove the sensor from the intake duct.
  3. Clean the sensor with MAF cleaner (do not touch the sensor elements).
  4. Reinstall the MAF sensor and reconnect the wiring harness.

5. Inspect Fuel Injectors

• Sub-steps:
  1. Remove the fuel rail to access the injectors.
  2. Check for clogged injectors and clean them using an injector cleaning kit.
  3. Reinstall the fuel rail and ensure injectors are seated properly.

6. Test and Replace Oxygen Sensors if Necessary

• Sub-steps:
  1. Use a multimeter to check the voltage output of the upstream oxygen sensor.
  2. If it is outside the normal range (0.1 - 0.9 volts while the engine is running), replace the sensor.
  3. Reinstall the oxygen sensor and reconnect the wiring.