Issue with W204 2008 C220 CDI Glow Plugs.....Help!

[Ryan Forgoine]

Hi folks,

I have a 2008 C220 CDI, last month a glow plug light came on during a cold start(stayed on for approx. 1 minute after driving away) and I changed all 4 glow plugs(to Lucas), however since then during a cold start, the light is staying on for the same amount of time. I put a diagnostic machine on it, and there is a fault showing up with glow plug 3 stating a 'Short circuit to ground'.

This makes me think that this is an electrical issue further back, and possibly nothing to do with the actual glow plug?

Has anybody else came across this and could offer any help/advice?

I would love to be able to sort this myself without having to take the car to an auto spark!

Cheers!
Ryan

 

[NBurns]

Hi folks,

I have a 2008 C220 CDI, last month a glow plug light came on during a cold start(stayed on for approx. 1 minute after driving away) and I changed all 4 glow plugs(to Lucas), however since then during a cold start, the light is staying on for the same amount of time. I put a diagnostic machine on it, and there is a fault showing up with glow plug 3 stating a 'Short circuit to ground'.

This makes me think that this is an electrical issue further back, and possibly nothing to do with the actual glow plug?

Has anybody else came across this and could offer any help/advice?

I would love to be able to sort this myself without having to take the car to an auto spark!

Cheers!
Ryan

I have the same issue on my 2005 S203 C220 CDI. Noticed it 3 years ago but was advised it would not affect the engine so never did anything to fix it. Now, with a bigger issue I felt it Was time now to fix this issue while getting my car back on the road again. So, following this thread.



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[Wighty]

Hi folks,

I have a 2008 C220 CDI, last month a glow plug light came on during a cold start(stayed on for approx. 1 minute after driving away) and I changed all 4 glow plugs(to Lucas), however since then during a cold start, the light is staying on for the same amount of time. I put a diagnostic machine on it, and there is a fault showing up with glow plug 3 stating a 'Short circuit to ground'.

This makes me think that this is an electrical issue further back, and possibly nothing to do with the actual glow plug?

Has anybody else came across this and could offer any help/advice?

I would love to be able to sort this myself without having to take the car to an auto spark!

Cheers!
Ryan

It is possible to test glow plugs in situ with an electrical test meter . I did mine a couple of years ago , I forget the exact procedure but I used YouTube initially .
It is basically putting one test meter probe on the glow plug , the other on the metal nearby and checking the resistance . If the number 3 is faulty it gives a different reading to the working ones .
The fault though may be in the glow plug relay which can get fried when the glow plug fails .

 

[thebiglad]

It's almost certain that the problem rests with the glowplug relay circuit thingamybob, rather than the plugs themselves. Apparently it's cheap and easy to change so I would recommend looking there.

 

[NBurns]

It's almost certain that the problem rests with the glowplug relay circuit thingamybob, rathan the plugs themselves. Apparently it's cheap and easy to change so I would recommend looking there.

Where is that?



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[thebiglad]

Where is that?



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[Ryan Forgoine]

It is possible to test glow plugs in situ with an electrical test meter . I did mine a couple of years ago , I forget the exact procedure but I used YouTube initially .
It is basically putting one test meter probe on the glow plug , the other on the metal nearby and checking the resistance . If the number 3 is faulty it gives a different reading to the working ones .
The fault though may be in the glow plug relay which can get fried when the glow plug fails .

Thanks for that reply! Have you any idea where the glow plug relay is? Somebody told me it was on the inner wing but I really can’t see anything on my 2008 W204. Somebody else mentioned that it could be easily accessible from underneath the car so that left me even more confused! If I could find it, I would change it as there is a good Mercedes breaker only a few miles from my house. Thanks

 

[thebiglad]

Thanks for that reply! Have you any idea where the glow plug relay is? Somebody told me it was on the inner wing but I really can’t see anything on my 2008 W204. Somebody else mentioned that it could be easily accessible from underneath the car so that left me even more confused! If I could find it, I would change it as there is a good Mercedes breaker only a few miles from my house. Thanks

Hi Ryan, if you watch the Youtube clip that I posted, all your questions will be answered.

 

[brianbrian]

N,S Front wing,disconnect and look on EBay for same, code No, should be on it.

 

[Ryan Forgoine]

N,S Front wing,disconnect and look on EBay for same, code No, should be on it.

Hi Brian, thanks for your reply. It appears that is correct for a 2006 W203 C220CDI (which my dad currently owns), but the only thing near my N/S front wing is the ABS control unit. I've heard from someone that the glow plug relay unit could be under the EGR valve at the back of the engine, which means accessing it from underneath the car most likely. The saga continues!

 

[Botus]

both the glow plugs and the control box (relay) should be considered as normal service items and should go in the bin circa 5 years 60k miles

 

[Albert38]

Hi Ryan. I am glad I found your thread. I have the same problem. 2008 C220. Changed all 4 glow plugs, now the pre-heat light stays on for about a minute. The same as your issue. I am 99% sure its now the relay as I have checked all 4 new plugs are working ok. Where was the relay situated and did the replacement fix the issue.

Many Thank
Paul

 

[ivanxxx]

A bit late reply, but the issue is with Glow plug module that will burn out if one of the glow plugs shorts to ground. To replace it is very difficult as its situated under EGR housing next to EGR valve, it has to be reached from under the car, very small space but enough to get it replaced. Hope this helps !