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

Solution

1. Preparation

• Ensure the vehicle is parked on a level surface and the engine is off.
• Gather necessary tools and parts.
• Disconnect the battery to ensure safety while working.

2. Inspect and Replace Transmission Fluid

• Tools Required: Transmission fluid pump, 17mm socket, fluid catch pan.
• Remove the transmission fluid pan using a 17mm socket, allowing the old fluid to drain into the pan.
• Inspect the fluid; it should be bright red and not smell burnt. If it appears dark or smells burnt, replace it.
• Replace the fluid filter if applicable, following the manufacturer's recommendations.
• Reinstall the pan with a new gasket, tightening bolts to specified torque (usually around 10 Nm).

3. Check and Replace Transmission Control Module (if necessary)

• Tools Required: OBD-II scanner, socket set.
• If additional codes indicate a faulty TCM, remove the old module by disconnecting the wiring harness and unscrewing it from its mount.
• Install the new TCM in reverse order, ensuring all connections are secure.
• Reconnect the battery.

4. Clear Error Codes

• Use the OBD-II scanner to clear all stored error codes.
• Perform a quick test drive to monitor for any reoccurrence of the P0700 code.