how to fix code P0700 on my Volkswagen Passat B8 (2015-2022)

Learn how to diagnose and fix P0700 transmission control issues in Volkswagen Passat B8 (2015-2022). Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Ensure the vehicle is on a flat surface and secure it with wheel chocks.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Transmission Fluid

• Tools Required: Transmission fluid pump, funnel, socket set
• Sub-steps:
  1. Remove the transmission fluid drain plug using a socket wrench and drain the fluid into a clean container.
  2. Inspect the drained fluid for metal shavings or a burnt smell; if present, further inspection of the transmission may be necessary.
  3. Replace the drain plug and torque it to the manufacturer-specified value.
  4. Use the transmission fluid pump to fill the transmission with the correct type of fluid (consult owner’s manual for specifications).
  5. Start the engine and let it idle, cycling through all gears to ensure fluid circulates properly.

3. Inspect Wiring and Connectors

• Tools Required: Multimeter, wire brush
• Sub-steps:
  1. Visually inspect the wiring harness and connectors to the TCM for any signs of wear, corrosion, or damage.
  2. Use a multimeter to test for continuity in the wiring; repair or replace any faulty sections.
  3. Clean any corroded connectors with a wire brush and apply electrical contact cleaner.

4. Test and Replace Transmission Control Module (if necessary)

• Tools Required: OBD-II scanner, multimeter
• Sub-steps:
  1. If the TCM is suspected to be faulty, use the OBD-II scanner to check for any specific TCM error codes.
  2. If testing indicates failure, disconnect the battery again and remove the TCM from its mounting location.
  3. Install the new TCM and ensure it is properly connected.
  4. Reconnect the battery and clear any existing codes using the OBD-II scanner.