why is my Volkswagen Passat B8 (2015-2022) battery overcharging

Solution

1. Preparation

• Disconnect the negative battery cable to ensure safety.
• Gather tools: multimeter, socket set, wire brush, battery terminal cleaner, and a load tester.

2. Inspect and Replace the Voltage Regulator

• Locate the alternator: Depending on the engine configuration, access may vary.
• Remove the alternator:
  1. Disconnect the electrical connectors.
  2. Remove the mounting bolts using the socket set.
  3. Carefully lift the alternator out of the engine bay.
• Inspect the voltage regulator: If the voltage regulator is integrated into the alternator, it may require a complete alternator replacement.
• Replace the voltage regulator (if separate):
  1. Remove the screws securing the regulator.
  2. Install the new regulator and secure it with screws.

3. Test and Replace the Alternator (if necessary)

• Testing:
  1. Connect the load tester to the alternator.
  2. Start the engine and observe the output voltage.
  3. If the output exceeds 14.5 volts consistently under load, replace the alternator.
• Replace the alternator (if needed):
  1. Position the new alternator in place.
  2. Reinstall the mounting bolts and tighten to manufacturer specifications (usually around 30-40 Nm).
  3. Reconnect the electrical connectors.

4. Reconnect the Battery

• Reattach the negative battery cable and ensure it is tight.
• Start the vehicle and check for proper operation.