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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Ensure the vehicle is on a level surface and securely lift it using jack stands.

2. Check and Replace Transmission Fluid

• Sub-steps:
  1. Locate the transmission pan and drain plug.
  2. Using a socket set, remove the drain plug and allow the old fluid to drain completely.
  3. Inspect the drained fluid for metal shavings or burnt smell.
  4. Replace the drain plug and refill the transmission with new fluid through the fill plug, using a funnel (consult owner’s manual for fluid type and capacity).
  5. Start the engine and cycle through all gears to circulate the new fluid.

3. Replace Transmission Filter

• Sub-steps:
  1. Drain the transmission fluid again if necessary.
  2. Remove the transmission pan by unscrewing all bolts (use a torque wrench to note the torque specs for reinstallation).
  3. Take out the old filter and replace it with a new one.
  4. Clean the transmission pan and install it back, ensuring a new gasket is used to prevent leaks.

4. Electrical Inspection and Repair

• Sub-steps:
  1. Inspect wiring harnesses and connectors to the TCM and transmission for damage or corrosion.
  2. Repair any damaged wires or connectors and ensure all connections are secure.
  3. If necessary, replace the TCM with a compatible unit, ensuring it is properly programmed.

5. Reconnect Battery and Clear Codes

• Sub-steps:
  1. Reconnect the battery terminals.
  2. Use the OBD-II scanner to clear the P0700 code and any other related codes.
  3. Take the vehicle for a test drive to ensure the issue has been resolved.