how do I fix the P0171 code on my Volkswagen Passat B8 (2015-2022)?

Solution

1. Preparation

• Gather tools and parts needed.
• Ensure the vehicle is on a flat surface and the engine is cool.
• Disconnect the battery to prevent electrical issues.

2. Inspect and Repair Vacuum Leaks

• Use a smoke machine or carburetor cleaner to identify vacuum leaks around the intake manifold and hoses.
• If any leaks are found, replace damaged hoses or gaskets as necessary.

3. Clean or Replace MAF Sensor

• Locate the MAF sensor in the air intake duct.
• Disconnect the electrical connector and remove the sensor.
• Clean the MAF sensor with MAF cleaner; allow it to dry.
• If cleaning does not resolve issues, replace the MAF sensor with a new one.

4. Check and Repair Fuel System

• Use a fuel pressure gauge to check fuel pressure; it should usually be within the manufacturer's specifications.
• If pressure is low, replace the fuel filter, inspect the fuel pump, and check for clogged injectors.
• Clean or replace fuel injectors as necessary.

5. Inspect and Repair Exhaust System

• Check for any cracks or leaks in the exhaust manifold and pipes.
• Repair or replace any compromised sections of the exhaust system to ensure proper operation.

6. Clear Codes and Test Drive

• Reconnect the battery and use an OBD-II scanner to clear the P0171 code.
• Start the engine and perform a test drive to monitor for any reoccurrence of the code.