Mercedes-Benz Check Battery Voltage on Cluster

How can I check the battery voltage of my Mercedes-Benz using my Instrument Cluster? By following the procedures below, learn to check your battery voltage using your instrument cluster. This step-by-step informational guide shows how to check the voltage on a Mercedes via the instrument cluster. Also, this guide can help determine if the alternator is bad.

Procedure

1. Get into the car and close the door.
2. Use the buttons on the steering wheel to display vehicle speed or temperature on the cluster.
3. Put the key in the ignition, and turn to position one (I)(right before you start the car)
4. Hit the reset button three times quickly. The reset button is on the side of the cluster.
5. You should see a value of 12 volts or more on your dash and hear a beep. This value represents the voltage coming from your battery.
6. Start the engine to check the voltage from the alternator.

Alternative Procedure

The steps may be different in more modern Mercedes cars (W212). If the above fails, try this:

1. Get into the car
2. Put the key in the ignition and turn to position two before starting the car.
3. Hold the call button and the “ok” button simultaneously on the left and right-hand sides of your steering wheel to enter the hidden menu.
4. You should see the options: 1. Vehicle data, 2. Roller test, and 3. Assist plus
5. Click “OK” on number 1, vehicle data.
6. You should see your battery voltage immediately displayed on the screen

When you first see the voltage on display, you see the battery voltage. Afterward, you can start the engine and check the alternator voltage.

What the Voltage Readings Mean

• Engine off, about 12.6 V or higher: battery fully charged.
• Engine off, about 12.2 to 12.4 V: partly discharged; charge it.
• Engine off, below 12.0 V: badly discharged or failing battery.
• Engine running, about 13.5 to 14.8 V: alternator is charging normally.
• Engine running, under 13 V or over 15 V: charging system problem.

Newer Mercedes models may not offer these hidden menus. A scan tool such as the YOUCANIC UCAN-II Pro shows live battery and charging voltage and reads power supply codes on supported models.

Frequently Asked Questions

What does it mean if my dash displays a figure less than 12 volts?

With the engine off, a reading below about 12 volts means the battery is badly discharged. Charge it with a battery charger (or jump start the car if you must), then retest. If it will not hold a charge, the battery likely needs replacing.

I started my car after this, and the value rose from 12 volts to 13.9 volts. Is this a problem?

It isn’t a problem, as your alternator now charges your battery. If anything, this signifies that your alternator is in good working condition.

Where is the reset button located?

It is located in the left area of your instrument cluster.

Do I need to access the battery to get these values?

You don’t need to access the batteries to get these readings.

How do I test a Mercedes-Benz alternator?

You will need a digital multimeter to measure DC to test the alternator on a Mercedes-Benz. Then, follow the steps in this guide.

Check these troubleshooting and repair guides for more help on your Mercedes-Benz.

Related Guides

• Mercedes-Benz Check / Test Battery Voltage with Multimeter
• Mercedes-Benz Check Battery Voltage No Tools Required
• Mercedes-Benz Hybrid High Voltage Battery: Resistance Check
• How to Find Mercedes-Benz Chassis Code via Instrument Cluster

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