Frequently Asked Question

We thought it would be nice to highlight some of the most frequently asked questions received over the years from our valued clients. Though there are no “fix all” solutions, our professionals at Euro Cars Southend keep educated on the latest known causes of vehicle issues and their respective solutions to remain at the top of their game within our industry.

Why won’t my driver’s window go up and down on my 2001 E320?

You may think it should be a bad switch or motor. We will hook up our lap top and read the codes and you’ll see that there is what’s called CAN communication issues as well as mechanical/electrical faults to look for. It could take considerable time to figure out if the control module under the seat is bad (possible water damage) or the one in the door itself. It may also be the wiring that is broken where the door hinges, that open and close 3 million times in a cars life. All this has to be determined before condemning a switch or motor. If that isn’t confusing enough for you, the answer to this particular question, in at least one instance was that the control module in the right rear door was bad and this kept the driver’s window from working. No need to scratch your head when hearing that sound for the first time, that’s why we are here to figure these things out for you.

My electronics go on/off on my 2003 E320. The battery is new, now what?

It isn’t the battery. Have you ever noticed a battery sign come on in your instrument cluster and noticed the stereo or air conditioning kept shutting down? Well, that is the small battery under the hood that controls those functions. It has to be checked at certain service intervals to make sure it is healthy. If it is low on charge or has corroded terminals it must be changed.

You mentioned CAN communication? What is that?

Please note: that there are other forms of communication now since vehicles are evolving constantly. Much like pony express, telegraphs, telephones, cell phones (analog, digital) and the internet…. All have the same end goal, to communicate, but they each have their own unique way to accomplish the same thing. There are several ways a vehicle communicates with itself. All the functions inside the vehicle talk to each other as well as under the hood too. Without getting too deep, I’ll explain this as simply as possible: Controller Area Network (CAN) electrical systems began to appear in new vehicles in 2003. Since then, more and more vehicles have been equipped with these systems and by 2008; virtually all BMW and Mercedes cars, trucks and SUV’s sold in the U.S. were CAN-equipped.

It’s important to know how CAN have made the electrical system in late model BMW’s and Mercedes Benz’s much more complicated than ever before. CAN is a communication standard that allows the various modules and computers in a vehicle to talk to one another via a common “data bus” circuit in the wiring system. Think of it as a high-speed party line allowing data and commands to zip back and forth from one module to another. This allows the Powertrain Control Module (PCM), antilock brake system, traction control system, stability control system, electronic steering, electronic suspension, automatic climate control system, keyless entry system, lighting control modules and dozens of other systems and modules to all be interconnected electronically. Many issues arise from a CAN fault, so it is important to keep you later model BMW and/or Mercedes maintained by dealer alternative professionals like we have here at Euro Cars Southend.