how to fix P0700 transmission control system malfunction in Volkswagen Golf MK7 (2015-2019)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to avoid any electrical shorts during repair.
• Ensure the vehicle is on a level surface and secure it with wheel chocks.

2. Inspect and Repair Wiring

• Remove the engine cover if obstructing access to the transmission wiring harness.
• Visually inspect the wiring harness for cuts, frays, or corrosion.
• If damage is found, repair the wiring using solder or appropriate connectors, ensuring proper insulation.
• Reconnect any loose connections securely.

3. Check and Replace Transmission Fluid

• Locate the transmission dipstick or fill plug.
• Remove the dipstick or fill plug and check the fluid level using a dipstick or by inserting a clean finger.
• If fluid is low, top off with the manufacturer's recommended transmission fluid (VW G 052 162 A2 is common for this model).
• If the fluid is burnt or contaminated, perform a full transmission fluid change by draining, replacing the filter, and refilling with new fluid.

4. Test and Replace TCM

• If the TCM is faulty, locate it (usually under the dashboard or near the transmission).
• Remove the TCM by disconnecting the wiring harness and unbolting it from its mount.
• Install the new TCM by reversing the removal steps and ensuring all connections are secure.

5. Reconnect Battery and Clear Codes

• Reconnect the battery terminal.
• Use the OBD-II scanner to clear the P0700 code and any other related codes.
• Start the vehicle and allow it to idle for a few minutes, checking for warning lights.