BMW Emergency Call System Error?

Replacing the BMW emergency call battery can be easily and quickly done at home. Here is a detailed step-by-step guide – illustrated using a BMW G01 (X3), identical for many models of the G series.

Step 1: Remove the roller cover in the trunk

Open the tailgate and press the “release button” on the right side of the roller cover. First pull the cover out of the holder on the right side, then on the left side.

Step 2: Remove the D-pillar trim

Next, remove the cover that surrounds the release button for the roller cover. You can simply clip it upwards and remove it.

Then carefully pull the D-pillar trim outward. For this, it is best to use a trim removal tool* to gently pry the plastic trim out of the clips. The process is identical on both sides of the vehicle.

INFO BOX:

When removing the D-pillar trim, the white clips may come loose from their guides. This is completely normal, and you can easily and effortlessly clip them back into place.

Step 3: Unclip the rear headliner

Release the clips of the headliner along the rear opening. Simply pull the headliner downward, which should be relatively easy. The advantage is that you don’t need to lower the entire headliner to access the telecommunications control unit (TCU).

Step 4: Replace the SOS battery in the telematics control unit

Now the telecommunications control unit (TCU) is visible under the headliner. The battery is located in the front right compartment of the control unit. It’s best to open the battery compartment of the control unit with a thin flat-head screwdriver. You can then easily remove the battery unless it falls out by itself.

Insert the new battery into the battery compartment and close it. You have now successfully replaced the SOS battery in the telecommunications control unit. You can now reassemble the headliner and plastic trim in reverse order.

Step 5: Clear error codes

After replacing the battery, the SOS system will work again, but the error will still be stored in the control unit. Without this step, the warning usually remains in the iDrive, even though the emergency battery has already been replaced. You can clear the error message with almost any diagnostic tool on the market. This means you don’t need an expensive OBD2 diagnostic device — you can also clear the code with a simple OBD scanner.

We have tested various diagnostic tools and can warmly recommend this article about the MUCAR CS4 diagnostic tool. This OBD scanner is ideal for occasional use, affordable, and can do a little more than just read and clear error codes. However, if you work with cars more frequently and want to step up your game, we recommend this article on the LAUNCH diagnostic tool.