Mercedes-Benz Electronic Ignition Switch EIS Failure

Learn how to fix and diagnose a Mercedes-Benz EIS (Electronic Ignition Switch) Failure. This guide will discuss the symptoms of an electronic ignition switch failure and possible solutions to fix the problem.

Signs or symptoms of having a faulty EIS (Electronic Ignition Switch) Failure

• Cannot turn the key when inserted on the EIS.
• The vehicle won’t start when twisting the key.
• Can turn the key, but the car won’t start.
• Cannot start the vehicle when it’s cold.

Reasons why the EIS (Electronic Ignition Switch) is not working

• Low battery voltage output.
• The voltage output on the wires to the device is high.
• The key is in the ignition while connecting the jumper cables.

Solutions on how to fix the EIS (Electronic Ignition Switch)

1. Insert a spare key into the EIS and try switching the vehicle on. If it works, then the problem is probably the vehicle’s key. To make sure, use the spare key for a few days to confirm that the problem is with the key, not the EIS.
2. Scan the vehicle using an OBD-II Diagnostic Scanner to check for fault codes. This procedure will work if the ignition works.
3. Connect a multimeter to the starter on the SAM (Signal Acquisition Module), set the multimeter to DC voltage, insert the key on the EIS, and turn the key. If no voltage is output, the module has a problem.
4. Replace the EIS; this solution will need to change the EIS’s VIN (Vehicle Identification Number) to match the vehicle’s VIN.
5. Remove the EIS on your vehicle and send it to a shop where they can diagnose and fix the EIS problem.

The YOUCANIC Full System Scanner can read and clear fault codes through every vehicle’s control module.

We hope you find the Mercedes-Benz Electronic Ignition Switch EIS Failure guide helpful. Check these troubleshooting and repair guides for more help on your Mercedes-Benz.

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