lillyblitz96

Mercedes M Klasse Hybrid Car Alarm Issue

My 2011 Mercedes M Klasse hybrid reports a defective additional battery alarm system and the alarm is non-functional. The error persists after deletion attempts. Could a discharged car battery be the cause? Has anyone encountered a similar battery problem and what was your diagnosis process?

4 comment(s)

Sounds familiar. I had a similar car alarm problem with my old Volvo. The auxiliary battery, specifically for the alarm, was shot. Have you checked its voltage? A standard battery test might not catch it.

Thanks, I hadn't considered a separate auxiliary car battery. Where is that typically located in the Mercedes M Klasse? Is it easily accessible for a voltage check, or will I have to disassemble half the car?

On my Volvo, it was a pain to get to, tucked away under the rear seat. I'm not sure about the Mercedes, but I'd wager it's not in an obvious spot. Honestly, given the potential complexity and to prevent any further electrical issue, taking it to a workshop might be best. They can perform a proper system diagnosis and save you a headache.

I'll take it to a workshop for a proper check. The repair cost should be around 330€. Hopefully, a new battery resolves the car alarm issue. Thanks!

Join the discussion now: