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

Learn how to diagnose and fix P0700 transmission control system fault in Volkswagen Passat B8 (2015-2022). Step-by-step guide with solutions and tips.

Solution

1. Preparation

• Ensure the vehicle is parked on a level surface and the engine is off.
• Gather tools and parts necessary for the repair.
• Disconnect the battery to prevent electrical shorts.

2. Check and Replace Transmission Fluid

• Tools Required: Transmission fluid pump, funnel, socket set, torque wrench.
• Instructions:
  1. Locate the transmission fluid dipstick or fill plug (consult the owner's manual for specific location).
  2. Remove the dipstick or plug and check the fluid level. If low, add the appropriate transmission fluid specified by the manufacturer.
  3. If the fluid appears burnt or contaminated, drain the old fluid using a transmission fluid pump, and replace it with new fluid according to specifications (usually VW G052162 A2 or equivalent).
  4. Replace the dipstick or fill plug and torque to the manufacturer's specifications.

3. Inspect and Repair Wiring to TCM

• Tools Required: Multimeter, wire stripper/crimper, electrical tape.
• Instructions:
  1. Visually inspect the wiring harness connected to the TCM for any signs of wear or damage.
  2. Use a multimeter to test for continuity in the wires.
  3. Repair any damaged wiring by stripping and crimping new connectors or using solder and electrical tape to ensure a secure connection.
  4. Reconnect the wiring harness to the TCM securely.

4. Replace TCM if Necessary

• Tools Required: Socket set, torque wrench.
• Instructions:
  1. If the TCM is found to be faulty, locate it (usually mounted on or near the transmission).
  2. Disconnect the battery again and remove the mounting bolts securing the TCM.
  3. Disconnect the electrical connectors from the TCM.
  4. Install the new TCM by reversing the removal process, ensuring all connections are secure.
  5. Torque the mounting bolts to the manufacturer's specifications.