how to fix P0700 code in BMW 3 Series E90/E91 (2005-2012)

Solution

1. Preparation

• Gather tools: OBD-II scanner, multimeter, socket set, torque wrench, transmission fluid, and a clean drain container.
• Ensure the vehicle is on a flat surface and secure it with wheel chocks and jack stands.
• Disconnect the negative battery terminal to prevent any electrical shorts.

2. Check and Replace Transmission Fluid

• Sub-steps:
  1. Remove the transmission fluid pan using a socket set.
  2. Allow the fluid to drain completely into the drain container.
  3. Inspect the old fluid for metal shavings or burnt odor; this may indicate deeper issues.
  4. Replace the filter if your model has one; follow manufacturer specifications for part numbers.
  5. Reinstall the pan, torqueing the bolts to the manufacturer's specifications (typically around 8 Nm).
  6. Refill the transmission with the correct type of fluid (refer to the owner’s manual for specifications).

3. Inspect and Repair Wiring/Connectors

• Sub-steps:
  1. Visually inspect the wiring harness and connectors leading to the TCM.
  2. Use a multimeter to check for continuity in the wires. Repair or replace any damaged wires.
  3. Clean any corroded connectors with electrical contact cleaner and reconnect.

4. Test and Replace TCM (if necessary)

• Sub-steps:
  1. After ensuring all connections are secure, reconnect the negative battery terminal.
  2. Use the OBD-II scanner to clear the P0700 code.
  3. Start the vehicle and check if the code reappears; if it does, consider replacing the TCM.
  4. Install the new TCM according to the manufacturer’s instructions and ensure it is programmed correctly if required.