how to fix P0171 code in Toyota Corolla E170 (2013-2019)

Solution

1. Preparation

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

2. Inspect and Repair Air Intake System

• Sub-steps:
  • Remove the air intake duct and check for cracks or loose fittings.
  • Replace any damaged hoses or components.
  • Reinstall the air intake duct and ensure all connections are secure.

3. Clean or Replace MAF Sensor

• Sub-steps:
  • Locate the MAF sensor on the air intake.
  • Disconnect the electrical connector.
  • Remove the MAF sensor using a Torx or Phillips screwdriver.
  • Clean the MAF sensor with MAF cleaner or replace it if necessary.
  • Reinstall the sensor and connector.

4. Check and Replace Fuel Filter

• Sub-steps:
  • Locate the fuel filter (usually in-line on the fuel line).
  • Relieve fuel system pressure by removing the fuel pump fuse and starting the engine until it stalls.
  • Disconnect the fuel lines using a line wrench, ensuring to collect any spilled fuel.
  • Replace the old fuel filter with a new one.
  • Reconnect the fuel lines and install the fuel pump fuse.

5. Inspect Fuel Injectors

• Sub-steps:
  • Remove the fuel rail to access the fuel injectors.
  • Inspect each injector for clogs or leaks; clean or replace as necessary.
  • Reinstall the fuel rail and ensure all connections are secure.

6. Clear Codes and Test Drive

• Sub-steps:
  • Reconnect the negative battery terminal.
  • Use the OBD-II scanner to clear the P0171 code.
  • Test drive the vehicle to monitor for any reoccurrence of the code.

Tools Required:

• OBD-II scanner
• Multimeter
• MAF sensor cleaner
• Fuel pressure gauge
• Socket set
• Torque wrench
• Line wrench

Parts Required:

• MAF sensor (if cleaning does not resolve the issue)
• Fuel filter
• Air intake hoses (if damaged)

Estimated Repair Time: 2-4 hours

Safety Warnings:

• Disconnect the battery before working on electrical systems.
• Relieve fuel system pressure before disconnecting fuel lines to avoid fuel spray.