Tuesday, 24 May 2011

If Microsoft made cars, you'd need to reboot them..

Except in this case, it would appear that the 'Microsoft' might be 'Mercedes'. Discovered that the car didn't want to talk to me this morning, it decided I, the key-holder, was a non-entity. No amount of button pressing would awaken the car from its nightly slumber, and the second key fared no better.

Odd, unlikely both keys would go flat, especially since the nice people at the Merc service desk take such pride in ensuring they swap out those CR2032s for us on a regular basis ;-) Tried the key for the other car, 'Chrirrup!' .. Ok, it's not radio interference..

Somewhere around here I guess I should have stopped thinking like I was debugging code, but as we'll see, that wouldn't have been such a bad idea ...

Thankfully, Mercs have "Mobilo Life", which, provided you meet some requirements, like keeping it serviced with them, etc.. gives you a handy call out service, for free.. I can imagine what my last car dealer would have said if I rang them up over a year after buying a 2nd hand car from them saying 'The car doesn't appear to want to start, do you fancy coming and having a look?", yet that's pretty much exactly what we told the Mobilo Life people, and they had an engineer, a proper Merc engineer with full diagnostic suite etc, arrive within an hour.

His initial conclusion matched mine.. battery is dead, the question is why? He repeatedly asked if we'd left anything on, lights, etc.. which is disturbingly difficult on this car, as pretty much everything turns itself off within 5 minutes, or will scream at you as you try to leave the vehicle with them on (except for parking lights, which are deliberately a little bit tougher to enable). Accepting my response that we hadn't, sensible engineer tests to see how much current the car is using when its supposed to be asleep.

Here's where it gets odd.. the car is munching away at 650ma while asleep, instead of the 10 or so he expected.. No aftermarket addons, although there is an aging mobile phone in the cradle.. We unplug the phone, let it go to sleep again.. still 650.. so he starts popping fuses under the bonnet one by one, still 650 (more at one stage when replugging a fuse woke something up).

Should point out he's not exactly guessing at this point, his uber touch panel of knowledge is doing its best to assist him, although I didnt notice clippy popping up anywhere asking if we were trying to fix a dead battery. His other widget is sucking the cars brain out through a cable, and both of them seem to agree that everything is fine, there's nothing to see here, move along.

Eventually, running out of other options, he tries the solution he refers to as a 'hard reset' ;-) To anyone who's ever used a computer, this would be familiarly known as 'turning it off and on again'. Awesome, of course a car has no plug, just the battery as its power.. and that's obviously lacking any switch.. so a quick disconnect/reconnect is called for.

After the system comes back up, we let it go to sleep again, and it returns to a nice happy sleeping level of just 10ma or so. Nice.

Conclusion, something in the cars network of electronic widgetry forgot how to go to sleep, and a reboot put it back into a known state so it sleeps again. Welcome to the age of rebooting your car to fix problems.

Of course, who knows if its a one off, and we'll never see this again.. or if we'll be seeing him again next Monday =) If it's the latter they get to take it away & figure it out ;p

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