Drive vehicle for 15 minutes or let it idle and the warning should reset on its own. If the error keeps coming up every morning, install a new battery. If that doesn't fix the problem, the problem most likely is due to a parasitic current draw.
Are you getting an ‘electric consumers offline’ message when you first start your car in the morning?
Unlike most other warning messages that are quite straightforward and intuitive, Mercedes-Benz Electric Consumers Offline may not be that easy to understand.
In addition, the absence of other apparent symptoms or corresponding issues only adds to the confusion. Many drivers are not sure what this message means and what to do when it occurs. To help with this, we will explain what triggers it and how to prevent it from happening.
Why does this message appear?
While the engine is running, it also turns the alternator, which generates electricity that is used for different purposes.
One of the major purposes is to provide electrical charge for fuel and ignition systems, as well as electrical components. This includes a wide range of creature comfort features, such as power windows, stereo, and so on.
Another important role of the charging system is to charge the battery and keep it at a sufficient charge level. Electricity then powers various systems when the engine is off and provides a charge for starting the engine itself.
However, there are certain situations in which the battery may not have enough charge to carry out these tasks. The main battery may even become flat and not have enough charge to start the car.
Even if it manages to start the engine, a sudden voltage drop may damage sensitive electronics inside various vehicle systems. To prevent this from happening, Mercedes Benz incorporated a special system that monitors the battery charge level while the engine is running.
If the voltage drops below a certain level, it will temporarily shut down all non-essential systems and corresponding functions. This will ensure there’s enough electricity to start the engine and ensure the uninterrupted operation of all vital systems.
Components that are affected by this temporary shutdown range from:
- heated seats,
- the infotainment system.
To warn the driver about the current situation, the onboard computer will also show the aforementioned message on the display.
What causes this message?
Many drivers are not aware that their cars use a certain amount of electricity even when they are not running. This is because various systems inside it remain in a standby mode, despite appearing to be completely off.
The rate of this discharge depends on how many systems inside the car are there, and may even be considered in certain situations. If the car is parked for a longer time, its battery may go flat even if the electrical system is in good condition.
The battery itself is another common cause, as even the best among them will fail with time. Depending on running conditions and the overall condition of the electrical system, they will last anywhere from three to six years.
However, things like extreme temperatures or deep discharging can shorten its lifespan. It is also worth knowing that many modern Mercedes Benz vehicles have two batteries, with each of them powering separate systems.
The main battery provides electricity for engine and drivetrain components, while the second one powers up auxiliary systems.
Similar to batteries, the alternator may lose its ability to generate enough charge as time goes by. Among potential causes, worn rotating parts or faulty voltage regulators are the most probable ones.
Modern cars have onboard computers that continuously monitor alternator voltage and warn the driver if it drops below certain values. Still, it is possible to have a rate of charge that will keep the car working, although not being able to fill up the battery.
Among likely causes, a parasitic drain is one of those things that even seasoned mechanics may forget to check. It happens when an electric component uses more electricity than it should, which drains the battery if the engine is not running.
The most common reasons for this are electrical shorts within the components or its failure to go to a standby mode. This has a similar effect as leaving the headlights on overnight, and can quickly discharge the battery.
Although there are many components that can cause this, a faulty amplifier is a very common fault with Mercedes Benz vehicles.
How to stop this from happening?
Start by analyzing your driving habits and try to find out if there is any correlation to whether the message should occur. If it appears only when the car is parked for a longer time, you should drive it more often for a while.
In case that helps, the most probable cause of the problem is the period between two rides, which is too long. One way of solving this issue is by using a trickle charger, which will keep the battery stay charged all the time.
Checking the condition of the battery and alternator is the next step, and there are two simple ways of doing this. One option is to visit a local parts store, as most of them will test the charging system for free.
You can also do this on your own, using a simple multimeter to measure the voltage between battery posts. With the engine off, readings should show at least 12 volts, as anything below that value shows a worn battery.
When the engine is running, these read-outs will reveal the alternator's condition, with 14 to 15 volts being the acceptable value.
As opposed to charging system issues, tracking down the sources of parasitic drains is a bit more complex. There are several ways of checking this, but the one we suggest involves measuring voltage drops across all fuses. This is a simple procedure, although it requires several preparation steps that will ensure accurate and meaningful readings. This video from HumbleMechanic will guide you through this procedure step-by-step.
As we explained here, an ‘electric consumers offline’ message will appear when the battery charge drops below a certain level. To ensure proper operation of all vital systems, the vehicle onboard computer will temporarily shut down all non-essential components.
Usually driving the vehicle or letting it idle for 15 minutes charges the battery and resets this warning message.
The reasons that cause this range from worn batteries or faulty alternators to parasitic drains.