MB Medic Mercedes-Benz Repair Guides, Service, How To DIY
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You insert the key into the ignition, but your Mercedes-Benz won’t start or crank. You notice that in the instrument cluster, you get the message “Computing Data Please Wait” and the key symbol shown in the picture above. The “Computing Data Please Wait” message indicates that the vehicle is processing key/drive-authorization data. On some older Mercedes-Benz models, this can occur when a replacement key is being synchronized. It can also remain displayed when there is a fault involving the key, EIS/EZS, EWM/ESM, or another component involved in drive authorization. If the car will not crank at all rather than sitting on this message, work through a Mercedes that will not start first, and if the trouble comes and goes with the key position, see ignition switch, EZS and EIS problems. If the key is new, then the solution may be simple. Rule out the cheapest cause first: a flat key battery can stop the car recognizing the key at all. If parts like EIS, ECU, or EWM are bad, that’s another story. If the EIS turns out to be the failed module, it can be cloned onto a replacement unit instead of buying and programming a new one, which keeps your existing keys working.
What the fault codes pointed to in our case
In this particular S-Class, our scanner was showing the following error message:
“B1016” IS NOT ENABLED FROM THE CONTROL MODULE EWM ELECTRONIC SELECTOR LEVER MODULE
This code points to an issue with the gear shifter module. Reading the codes from EWM, we noted the following code.
If the key is new, try this before replacing anything
- Connect a car charger to the main battery. Connect a suitable battery charger or power supply capable of maintaining stable vehicle voltage during the procedure. Avoid relying on a low-current battery tender if the battery may discharge while the ignition is on. A good choice would be the Schumacher Speed Charger.
- Insert the key into the ignition and turn to position two. All dash lights should turn on. If the key doesn’t turn, you may need to use YOUCANIC Full System Scanner to unlock the Drive Authorization System. If you remove the key from the ignition during this time, you have to start over.
- Leave the key in the ignition for at least 6 hours for the key to synchronize. We are not kidding. On some W220 vehicles, a replacement key may require an extended synchronization period. The time can vary, so do not treat six hours as a universal requirement. If the message remains indefinitely, or fault codes are present, diagnose the drive-authorization system rather than continuing to wait. Once the key is synchronized, you should no longer see the “Computing Data Please Wait” message in the instrument cluster, and the display should go back to showing the mileage.
It took about five and a half hours for the key to pair up with the car. Mercedes-Benz keys come pre-programmed when you order them from the dealer, and you usually don’t have to follow this procedure. This wasn’t the case for us; we were getting the error codes listed above. We did not replace the shifter module or any other parts to resolve this issue. After several hours of leaving the key in the ignition, the key synchronized with the car.
What is the Best Scanner to Unlock my Mercedes-Benz Drive Authorization System?
If you’re experiencing problems with your Mercedes-Benz, the YOUCANIC full system diagnostic scanner can be an invaluable tool for troubleshooting and diagnosing the issue. This scanner is designed specifically for use with Mercedes-Benz vehicles, allowing you to access and analyze data from your car’s various systems and modules.
With the YOUCANIC scanner, you can perform various diagnostic functions, including reading and clearing fault codes, monitoring live data, performing component activation tests, and more. This allows you to identify the root cause of the problem and take appropriate action to fix it, whether it involves replacing a faulty component, adjusting a system setting, or performing more extensive repairs.
By using the YOUCANIC full system diagnostic scanner, you can save time and money by avoiding unnecessary trips to the mechanic and performing repairs yourself. Plus, with the ability to access real-time data and diagnostics, you can stay on top of your vehicle’s maintenance and prevent potential problems before they occur.
Before you buy parts, scan every control module, not just the engine. It shows the root fault behind the warning lights and tells you whether the problem is still active. See how to do a full health check.
