my Volkswagen Passat B8 (2015-2022) has a check engine light and rough acceleration, what's wrong?

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative battery terminal to ensure safety.

Tools Required:

• OBD-II scanner
• Socket set
• Multimeter
• Torque wrench

2. Address Fault Codes

• Use the OBD-II scanner to retrieve and record any fault codes.
• Research the fault codes to identify the specific component or system at fault.

3. Replace Faulty Components

• If the codes indicate a faulty spark plug or ignition coil:
  • Remove the engine cover (if applicable).
  • Disconnect the wiring harness from the ignition coil.
  • Remove the ignition coil bolts and extract the coil.
  • Replace with a new ignition coil and torque to manufacturer specifications.
  • Reinstall the spark plug if it is worn or damaged.

4. Inspect and Clean the Throttle Body

• Remove the air intake duct to access the throttle body.
• Use throttle body cleaner to gently clean the throttle plate and surrounding area.
• Reassemble the air intake duct securely.

5. Verify Fuel System Integrity

• Connect a fuel pressure gauge to the fuel rail.
• Start the engine and check that the fuel pressure meets manufacturer specifications.
• If pressure is low, consider replacing the fuel pump or filter as necessary.

6. Reassemble and Reconnect

• Reconnect all components and wiring harnesses that were removed.
• Reconnect the negative battery terminal.
• Clear any fault codes using the OBD-II scanner.