what does it mean if my Volkswagen Passat B8 (2015-2022) has a B1086 code

Solution

1. Preparation

• Gather tools and materials: OBD-II scanner, multimeter, socket set, and cleaning supplies.
• Ensure the vehicle is parked in a safe location with the ignition off.

2. Inspect and Clean Battery Terminals

• Disconnect the negative (-) battery cable using a socket wrench.
• Clean any corrosion from the battery terminals using a wire brush and a baking soda solution if necessary.
• Reconnect the battery terminal securely.

3. Test Battery Condition

• Using a multimeter, measure the battery voltage. If it’s below 12.4 volts, charge the battery or replace it if it cannot hold a charge.
• If the battery is good, proceed to test the alternator.

4. Check and Test Alternator Output

• Start the vehicle and measure the voltage at the battery terminals again. It should be between 13.8 and 14.4 volts.
• If the output is low, the alternator may need to be replaced.

5. Inspect Wiring and Connectors

• Visually inspect the wiring harness connected to the battery and alternator for any signs of wear or damage.
• Repair or replace any damaged wiring or connectors.

6. Clear the OBD-II Code

• Use the OBD-II scanner to clear the B1086 code after all repairs are completed.
• Take the vehicle for a test drive to ensure the code does not reappear.