how to fix P0171 Lean code on Toyota Tacoma N300 (2016-Present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety during repairs.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum hoses and connections around the intake manifold.
  2. Use a smoke machine or carburetor cleaner to locate leaks.
  3. Replace any damaged hoses or seals found during inspection.
• Tools Required: Smoke machine or carburetor cleaner, pliers.

3. Clean or Replace MAF Sensor

• Sub-steps:
  1. Disconnect the MAF sensor connector.
  2. Remove the MAF sensor from the air intake duct.
  3. Clean the sensor element with MAF cleaner spray.
  4. Reinstall the MAF sensor and reconnect the electrical connector.
• Tools Required: MAF cleaner spray, screwdriver.

4. Check and Adjust Fuel Pressure

• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail test port.
  2. Start the engine and observe the fuel pressure reading; it should be within manufacturer specifications (typically 50-60 psi).
  3. If the pressure is low, inspect the fuel pump and replace if necessary.
• Tools Required: Fuel pressure gauge, socket set.

5. Inspect and Test Fuel Injectors

• Sub-steps:
  1. Remove the fuel injector connectors and inspect for corrosion or damage.
  2. Use a multimeter to test the resistance of each injector; it should match manufacturer specifications.
  3. If any injectors are faulty, replace them with new units.
• Tools Required: Multimeter, socket set.

6. Verify Engine Coolant Temperature Sensor

• Sub-steps:
  1. Locate the engine coolant temperature sensor.
  2. Use a multimeter to check if the sensor is within the specified resistance range at various temperatures.
  3. Replace the sensor if it is out of specification.
• Tools Required: Multimeter, socket set.