C270 CDI Glow Plug Relay

[deonjoubert]

Hi there, my wifes car went for a service last Friday and the MB workshop changed all 5 five glow plugs aswell as the relay telling me that if two or more glow plugs failed the sonsor allso fails. After checking the glow plugs only one was faulty. I replaced the original relay and it seems te be working fine. Anybody knows if their story is true or not? They also replaced the Air Mass Meter and the following morning it went traight back into limp mode and I am now on my back to the workshop with car.

 

[carat 3.6]

Welcome to the forum.

Do you know the part no of the relay you changed? I only ask because my local stealer told me it was built in to something else?

 

[jaymanek]

They will always prefer to replace them as a set as often another will follow if one has failed which means double labour for them.

 

[AMG19]

I don't think it is true that you must replace the relay if 2 or more glow plugs go.
The car being in limp mode again sounds like they have miss diagnosed the fault to begin with.

 

[Tinkerer]

If it is going 'back' into limp mode then presumably they knew of this before they serviced it and hence changed the MAF, next port of call I suspect will be the EGR valve. I have never changed glow plugs in sets and so far (fingers crossed) have never had a problem with immediate subsequent failure. Have had a large amount of cobblers from MB dealerships ..... too much to list here.

 

[deonjoubert]

Thanks for all the replies. The old glow plug relay is still working fine and after further investigation the air inlet pipe had a crack in it and that resulted in a "low boost presure" fault that caused the car to go into limp mode. All the fault codes are cleared for now and the car is doing fine. Thanks again. Deon.