how to diagnose P0700 transmission code in BMW 3 Series F30/F31 (2012-2019)

Solution

1. Preparation

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

2. Inspect and Replace Transmission Fluid

• Tools Required: Socket set, fluid pump, transmission fluid (consult owner's manual for specifications).
• Sub-steps:
  1. Remove the transmission fluid drain plug using the socket set.
  2. Allow the old fluid to completely drain into a suitable container.
  3. Inspect the old fluid for metal shavings or burnt smell.
  4. Replace the drain plug and tighten to manufacturer torque specifications (typically around 30 Nm).
  5. Use a fluid pump to fill the transmission with new fluid through the fill port until it reaches the proper level.
  6. Reinstall the fill port cap securely.

3. Repair or Replace Wiring/Connectors

• Tools Required: Multimeter, wire stripper, soldering iron (if necessary).
• Sub-steps:
  1. Use the multimeter to check for continuity and resistance in the wiring harness connected to the TCM.
  2. If damaged wiring is found, cut and strip the affected section.
  3. Reconnect the new or repaired wire using solder and heat shrink tubing for insulation.
  4. Secure all connectors and ensure they are free of corrosion.

4. Replace TCM (if necessary)

• Tools Required: Socket set, torque wrench.
• Sub-steps:
  1. Locate the TCM (usually found near the transmission or under the dashboard).
  2. Disconnect the electrical connectors carefully.
  3. Remove any mounting bolts with the socket set.
  4. Install the new TCM and secure it with bolts to the specified torque.
  5. Reconnect all electrical connectors securely.