Assistance required for no engine turnover

[SerendipitySage]

I am utterly perplexed by my 2017 C-Class AMG 4MATIC; it functioned flawlessly when parked, yet the following morning it exhibited no crank. The doors unlock, the dashboard illuminates, but there is no cranking action. I have examined every fuse and relay, including the concealed high-powered fuses, all of which are intact. The starter relay receives voltage at pin 30, but there is no voltage at pin 86. I have bypassed the relay, and the vehicle cranks but fails to start; it seems there is an obstruction preventing voltage from reaching pin 86. Any suggestions or advice would be greatly appreciated.

[KOOLCAR]

It may pertain to the security aspect; are both keys identical in this regard?

[ELGIGANTE]

Is it equipped with EIS-type ignition? Occasionally, a malfunctioning EIS may provide you with nuanced (and overt) alerts prior to its total failure, potentially leaving you in a difficult situation.

My 2006 C class experienced an incident where, after refuelling, the instrument gauges remained stationary and the windows failed to operate; I drove it home without issue. Over the subsequent days, while parked on my property, I tested both keys at various intervals, yielding inconsistent outcomes, including instances where the engine would not crank; it would have been quite unfortunate had this occurred at the service station.

I removed the EIS and dispatched it for repairs; it has functioned well ever since.

If your vehicle lacks EIS, I have merely squandered your time.

I trust that everything will turn out favourably.

[SerendipitySage]

Hello, I appreciate your response; however, my vehicle does not possess that feature. I initially believed it was the issue since it occurred with my neighbor's car. My car also lacks a steering lock, which I assumed was the cause, but it seems that is now standard due to previous complications.

[SerendipitySage]

Greetings, I possess only a single key; however, I am contemplating whether it is a security immobiliser issue or if the key itself is the problem. I believe a diagnostic assessment will be necessary. Thank you for your response.