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

Solution

1. Preparation

• Tools Required: OBD-II scanner, fluid pressure gauge, socket set, multimeter, transmission fluid.
• Ensure the vehicle is parked on a level surface and the engine is off.
• Disconnect the battery to prevent electrical shocks.

2. Check and Replace Transmission Fluid

1. Remove the transmission fluid dipstick and inspect fluid level.
2. If fluid is low, add the manufacturer-recommended transmission fluid until the correct level is reached.
3. If the fluid is dirty or has a burnt smell, drain and replace it.
   • Place a drain pan under the transmission pan.
   • Remove the transmission pan bolts using a socket set.
   • Carefully lower the pan and drain the fluid.
   • Replace the filter if applicable.
   • Reinstall the pan with a new gasket and torque bolts to manufacturer specifications (usually around 8-10 Nm).

3. Inspect and Repair Electrical Connections

1. Visually inspect the wiring harness connected to the TCM and transmission solenoids for damage or corrosion.
2. Use a multimeter to test for proper voltage and ground at the TCM connector.
3. Repair or replace any damaged wires or connectors as necessary.

4. Replace Transmission Control Module (if necessary)

1. If the TCM is found to be faulty, remove it by disconnecting the electrical connector.
2. Unscrew the TCM mounting bolts and remove the module.
3. Install the new TCM by reversing the removal process and ensure proper connection.

5. Reconnect Battery and Reset Codes

• Reconnect the battery terminals.
• Use the OBD-II scanner to clear the P0700 code and any related codes.