how to troubleshoot P0700 code on BMW 3 Series E90/E91 (2005-2012) transmission problems?

Solution

1. Preparation

• Gather tools and parts required.
• Ensure the vehicle is parked on a level surface with the engine off.
• Disconnect the battery to prevent electrical shorts.

2. Check Transmission Fluid

• Tools Required: Transmission fluid dipstick or funnel, clean cloth.
• Remove the transmission dipstick and check fluid level.
• If low, top off with the manufacturer-recommended transmission fluid (typically ATF).
• Inspect fluid for any burnt smell or metal shavings; if present, a transmission service may be necessary.

3. Inspect Wiring and Connectors

• Tools Required: Multimeter, screwdriver, flashlight.
• Visually inspect the wiring harness for frays or damage.
• Use a multimeter to check for continuity in the wiring.
• Clean connectors with electronics cleaner and reassemble securely.

4. Test the TCM

• Tools Required: OBD-II scanner, multimeter.
• Use the OBD-II scanner to check for any additional transmission-related codes.
• If no codes are present, use the multimeter to test power and ground supply to the TCM.
• If the TCM is unresponsive, consider replacing it.

5. Reconnect Battery and Clear Codes

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0700 code and any other stored codes.
• Start the engine and check for any reoccurrence of the code.