Infiniti M's Electrical Nightmare: Voltage Issues Exposed

Hey there! I had a similar issue with my 2013 Infiniti Q70 Diesel (got some basic car maintenance experience). Those symptoms sound exactly like what I dealt with classic signs of a failing battery that was causing weird electrical behavior. Took it to my regular workshop and they diagnosed it as a completely dead battery that was actually damaging other electrical components. Got it replaced for around 290€ at my trusted mechanic, and all those symptoms disappeared instantly. What's your mileage and when was the last battery change? Also, any warning lights on the dash? This info would help me share more relevant details from my experience with the Q70. Just make sure you don't wait too long a bad battery can cause more expensive problems down the line!

Thanks for sharing your experience! My battery is actually fairly new (changed it 8 months ago), and I'm at 102213 KM. Had my last service just a couple weeks back where everything electrical checked out fine. That's what makes this so puzzling these symptoms just started showing up out of nowhere. Did your mechanic check anything else besides the battery when you had similar issues? Starting to wonder if it might be the alternator or maybe some wiring issues.

Hey again! You know what, your situation does sound a bit different from what I initially thought. On my Q70, when I had the battery replaced, the mechanic actually did a full electrical system check (standard procedure at my shop). Come to think of it, after my battery replacement, I had a similar issue pop up about 6 months later turned out my alternator wasn't charging the battery properly. The symptoms were practically identical to what you're describing. My mechanic tested the alternator output and found it was only putting out about 12V instead of the normal 13.5-14.5V range. Cost me about 450€ to get the alternator replaced, but it fixed everything. These Infiniti diesels can be a bit finicky with their electrical systems learned that the hard way! Since your battery is new, I'd definitely get the alternator checked. Could also be a loose connection or a faulty voltage regulator (that's what controls the alternator's output). If it helps, my car was at around 98000 KM when this happened. Honestly, given your mileage and the symptoms, it's sounding more and more like an alternator issue. Maybe get a second opinion from another mechanic? Just to be sure before you start replacing parts.

Thanks a lot for the detailed response! You might be onto something with the alternator theory especially since our cars had such similar mileage when the issues started. I'll definitely get it checked out first thing tomorrow morning. I've got a good independent Infiniti specialist nearby who can test the alternator output. Really appreciate you mentioning those specific voltage numbers too gives me something concrete to discuss with the mechanic. The voltage regulator is also a good shout hadn't thought about that. Will make sure they check both. Better to get it sorted now than end up stranded somewhere! Thanks again for taking the time to share your experience it's been super helpful. I'll update the thread once I find out what's actually causing the problem.