W212 E-Class engine runs but no gears and all warning lights

[Watchman]

My wife's 62-reg E has stood a week on the drive. Went to start it this morning and it starts just fine but all the dashboard warning lights are on, and it won't allow me access to any electrical-operated controls such as gears, electric seats, heating or COMAND.

It's been cold this week so I let it warm up a bit but the fan is running 100% so the temp isn't rising above 70 degrees.

I expect the battery was a little low triggering all these failures but as the car starts, surely the correct voltage will be presented once its running.

Is there any way to reset it?

I do have an ODBII connector for fault finding and reseting but my wife has taken my car this morning with my ODBII connector. Is that likely to help?

[Watchman]

Turned it off and left it a while, to see if the heat of the engine would soak through into the sensors and components, and restarted 15 mins later. This time, most of the warning lights went out and it responded to my request for gears. Took it for a spin to properly warm it up but the check engine light is still on. I'll try it again in 30 mins then I'll mess about with my OBDII connector when my wife returns.

[Watchman]

Thanks - I forgot it had the second battery, and I agree with you - they are sensitive to the cold. I'm surprised that only a week could cause this though. It's conceivable that someone could leave their car at an airport for a period of time and find it useless upon their return.


Anyway, the car runs OK now - only the engine warning light still on but the OBDII diag suggests it's both the "network" (comms to the brake sensors in the expanded explanation), and "Powertain Vehicle Speed Sensor". I'll see what happens over the next couple of days. If it all clears, I'll leave it but make sure I run the car when my wife's away in future. If it doesn't clear, I'll book it into the local Merc dealership when she's back from the next trip.

Thanks for the suggestions and confirmation of what I thought it might be.

[Watchman]

Thanks. It's all working properly again so I'll make sure it gets a run every 2 to 3 days when she's away but my old ML had starting issues related to a dying battery so I'll keep an eye on it.

[Watchman]

T5R+ said:

ML battery compartment location and battery exchange methodology - 10/10 to whoever approved that

Ha..!! The reason why I lived with it and didn't change it.

I watched an Indian chap in a clean white shirt change his on YouTube. He looked knackered and his shirt ruined at the end.

[Watchman]

One of your batteries is toast. Replace and the problem will go away. Likely to be the main starter battery rather than the ancillaries battery.