On the Friday Hurricane Rita was about to hit town while I was 30 miles closer to the storm than my home, my ML failed to start. Technically, it started, but it failed to continue running. Compounding the problem was the fact that the battery chose the exact same moment to die (5 years old). Some guy gave me a jump but each time it started it failed again. I had it towed and stored for the weekend. Monday I was going to take it to my mechanic so I pulled out the spare key (the one I would leave with him) and tried to start it, before I called for another wrecker. It fired right up and ran fine. No OBD ll codes. He changed the battery while we discussed the starting problem. He said it sounded like the VAT (vehicle anti theft system). He said GM keys go bad a lot and thats what they do. We concluded that the spare key was still good but my regular key had gone bad. He was right. When I got home the main key still had the same problem. Spare key worked fine. Ironically I had 2 spare keys with me on Friday but did not know to suspect the main key.

Key batteries had nothing to do with it. I put in a 3rd key which hasn't had batteries in it for years because it got wet and fried the circuit board. Started right up, several times.

Always carry a spare key in the car somewhere. My key died at the worst possible time. Even AAA said they couldn't find me a wrecker due to the hurricane, I was truly on my own, in a ghost town due to 2,000,000 evacuees.

Note. I had had the dealer look at it 2 days earlier but they couldn't find a problem because I gave them the good spare key to use. But having said that, my general mechanic figured it out using th same key and with less brand knowledge than the dealer. Go figure.

 

Sorry to hear about your bad luck.
I heard, that in new vehicles the key and car "talks" to each other and just like with humans, sometimes they miscommunicate. To fix it leave the key in the ignition in the "on" position for couple of minutes and let them settle the dispute.
If that only could work with humans...
Don't you just hate those electronic gizmos, that fail and nobody knows how to deal with it?
For the old cars big hammer and cold chisel was the tool, that fixed it the most.
BTW the 7-years old battery in my ML still works great and I wonder how long can I expect it to dc so. Maybe it would be a time to check the electrolyte level.... for the first time.

 

Your reply gave me hope but alas it was not so. I let the key talk in the on position (radio works but no idiot lights) for 2 minutes. No go. So I tried it with the idiot lights on too. Still no go. just for kicks I retrieved the key that has no batteries in it: started right up. So my dead key remains concealed under the car incase I lock myself out. But if someone finds it they can't drive the car away. Clever huh?

 

Where exactly did you hide it?

 

Nice try. But I guess you know they don't fit in those magnetic key holders.