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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the parking brake is engaged.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Check and Replace Transmission Fluid

• Tools Required: Socket set, transmission fluid pump, catch pan, funnel.
• Remove the transmission drain plug and allow fluid to drain into the catch pan.
• Inspect the old transmission fluid for metal particles or burnt smell; replace if necessary.
• Reinstall the drain plug with a new seal, torque to manufacturer specifications (typically around 30 Nm).
• Fill the transmission with new fluid (consult the owner’s manual for the correct type, usually ATF or specific BMW fluid) using the funnel and fluid pump.

3. Inspect and Repair Electrical Connections

• Visually inspect the wiring harness connected to the TCM for damage or wear.
• Disconnect the TCM connector and clean the terminals with electrical contact cleaner.
• Reconnect and ensure the connector is seated properly.

4. Replace Faulty Sensors

• If the vehicle speed sensor or transmission range sensor is found faulty during diagnostics:
  • Tools Required: Socket set, screwdrivers.
  • Remove the faulty sensor by unscrewing it from its mounting location.
  • Install the new sensor, ensuring it is properly seated and secured.
  • Reconnect the wiring harness to the new sensor.

5. Reconnect Battery and Clear Codes

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the fault codes.
• Perform a test drive to evaluate transmission performance.