2002 C270CDI AUTO gearbox in permanent limp home mode.

[nikolaymk]

Hi,

Just bought a very nice C270 CDI Estate through the trade but the gearbox is not changing gears at all. It's permanently stuck (probably in second gear) in limp home mode, the tiptronic function doesn't work at all and I feel a jolt when shifting into drive or reverse.

My scanner flags two stored codes which I can clear but they reappear as soon as the ignition is switched on.

P2600 - The voltage supply of circuit 87 has undervoltage.
P2602 - The voltage supply of the valves is faulty.

A couple of things to point out. We've checked the gearbox oil and topped up about 1 litre up to the max mark. Hasn't made any difference. Also, the car had to be jump started at the auction when we were looking at it.

I hope someone has an idea. Your help is much appreciated. Nick

 

[turbopete]

sounds like a new battery is required. I seem to think low battery voltage can cause this

 

[nikolaymk]

Thanks for the quick reply, do I have to reset anything other than the fault codes after the new battery is fitted?

 

[Cole@MBS]

As Pete above, check the battery, not common for the C.class to have this fault mind!!!!!

 

[Alex Crow]

Pete has it right, those codes point straight to the duff battery - you said it needed jump starting...

 

[umblecumbuz]

And regrettably, it isn't 'limp home mode'. A lot of MB owners wish it was - at least, they would get home when something went wrong!

Hope you get this small hiccup quickly sorted!

Baz

 

[nikolaymk]

I thought it was "limp home mode". Is it a different mode then or just the way this fault manifests itself. It's a nasty thing to happen just because of an old battery. Thanks for all your help guys!

 

[jibcl500]

I'd check the pilot bush on the gearbox. Oil in the bush gives the under voltage as it aint getting any.


jib

 

[nikolaymk]

Hi, just a quick update: New battery fixed the problem completely, thank you all for your help!