Typically you get a BATTERY/ALTERNATOR VISIT WORKSHOP warning when the electrical system voltage in the car is below 12.6 volts. When the car runs, the alternator produces electricity, and the voltage should be above 13.5 volts. If you have a multimeter like this, you can connect it to the battery terminals to get a voltage reading.
The main reasons for BATTERY/ALTERNATOR VISIT WORKSHOP:
The main battery is near the end of its life.
The secondary (Aux) Battery needs replacing (if applicable).
Just because you can start the car in the morning doesn’t mean your main battery is in good condition. The battery may be near the end of its life and doesn’t provide the necessary. Check the main battery before starting the car if you have a voltmeter. It should have about 12.5 volts. If it is lower than 12, you need a new battery.
Here is a simple test you can perform if you get Battery Defective message at start-up. Let the car run for about 10 -15 minutes. Then turn off the car, make sure all the lights are off, and nothing is on for 30 seconds. Then start your car back up again. Do you still get the Battery Defective message again? If you don’t, your main battery is not holding a charge properly, especially if the car has been sitting for a long time. You will be ok to drive the car but replace the battery as soon as possible before it does not last very long. Mercedes uses battery group 49, and if you want to save some $$$, you can get an AGM battery, which the dealer uses for less on Amazon. Here is a highly rated battery on Amazon that will fit Mercedes Benz cars.
More often than not, the real problem is the voltage regulator in the alternator. You can replace just the voltage regulator if you know the real problem. Otherwise, it would be best if you replaced the whole alternator. Before replacing the alternator, ensure your battery is not the problem. Go to Advance Auto Parts or AutoZone to troubleshoot your car and have them do a FREE alternator/battery check. This test may be able to point you in the right direction.
Some Mercedes Benz models, such as the E or CLS Class, have a secondary battery. This is a smaller 12-volt auxiliary battery that is used as a backup. The system also checks this battery’s voltage; if it is lower than 12.6 volts, you will get the error on your dashboard. So if you replaced the main battery and were wondering why you are getting the Battery/Alternator Visit Workshop message, check this battery as well. Before you start the car after sitting for a few hours or overnight, grab a multimeter and check the voltage at the secondary and the main battery. If you have less than 12.5 volts at either one, you know your problem. You can get a multimeter for testing on Amazon for about $20, and they are very easy to use even if you have never used one before. For example this one,
4. Battery Terminals
This may sound like to obvious, but it was driving me crazy one time on an E Class. I was getting the Battery Visit Workshop message and knew I had good batteries. The negative post’s battery terminal was loose, causing this problem. You can remove the terminal connections and clean them up just to be sure. I use sandpaper around the terminal post and at the cable end connection to clean up.
These are the main reasons you get the Battery Alternator Visit Workshop Error Message. If you need to replace any of the batteries, you can order them on Amazon using the links below and also help us at the same time.
You may get ElectronicConsumers switched off when the car’s computer has detected a low voltage. This happens when the main battery is old and goes wrong. Test the main battery and replace if defective.
Before troubleshooting, you must know if your car has one or two batteries. Why do some models have two batteries?
According to Mercedes-Benz, the main battery, usually found in the trunk, supplies the onboard electrical system in regular operation. While the secondary (auxiliary battery is a short-time backup for the power supply in the event of the onboard system battery failing. E Class W211, CLS Class, for example, has two batteries.
The sequence of the electrical system:
• The battery control module monitors the operating states and the vehicle’s voltage conditions.
• Depending on the performance measured for the battery, consumers can be switched off in 2 priorities (switched off using CAN message). In this case, you may get an error message: malfunction electrical consumers switched off. Check your batteries and alternator.
• The battery control module (BCM) activates the battery isolating relay (K57/2) if necessary. A distinction is made between 2 states:
– recharging of additional battery
– engaging additional batteries in critical on-board network situations
N82 Battery control module (BCM)
The battery control module is installed in the trunk to monitor the batteries (the installation position depends on the equipment. Minispare/full-spare wheel or Tirefit).
The tasks of the battery control module are:
• Detecting the battery state
• Switching off consumers (energy management)
• Connecting the additional battery if necessary (through the battery isolating relay K57/2)
What Scanner Can I Use to Troubleshoot Mercedes-Benz Alternator Problems?
If you’re experiencing problems with your Mercedes-Benz, a YOUCANIC full system diagnostic scanner can help you troubleshoot the issues. This advanced diagnostic tool can read and interpret the fault codes stored in your car’s computer system, providing detailed information about any problems with the engine, transmission, brakes, or other critical systems.
The YOUCANIC scanner can also perform diagnostic tests on various systems, including the ABS, airbag, and steering systems, to help pinpoint the root cause of any issues. With this information, you can make more informed decisions about repairs and maintenance, saving time and money on costly repairs.
If you have any questions or comments, please post them below in the comments section.