2007 E320CDi glow plug light on

[DrNick]

The glowplug light on my 2007 E320CDi has come on.

The light comes on as normal, goes off and then I start the engine. Immediately the light comes back on and stays on for about a minute.

It started behaving like this for a week or so, then it cleared itself and behaved normally for a couple of weeks.

Now its back to misbehaving. The resistance of the plugs has been measured and they are pronounced ok.

The light does not stay on if starting from a warm engine.

Any clues before I start looking for glow plug relays?

TIA

DrNick

 

[johnny 1]

It could be a glow plug need replacing


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[4life211]

it is glow plug relay.

 

[wu56Shoozz]

^ Wot He Said.

Don't buy an aftermarket relay as their crap (Ask me how I know) I was advised to buy 6 new plugs and a relay as the relay fails it burns out the glowplugs when used...look on ebay for a company called mercedesofnewcastle typed like that .. I've managed to negotiate a bit of discount of them and they've been really helpful..

 

[Orwic]

I had a similar issue. The fault was diagnosed as a faulty glow plug. Replaced them all (just a few days ago) and all OK now. Hope so, anyway, as I haven't used the car since...

 

[KennyN]

Normally a faulty relay leads to extended cranking when cold and the GP light coming back on is one or more plugs being faulty.

Plugs are around £70 a set and the relay is double that, both are easy to DIY if you have the time and tools.

The fact that is ok sometimes may point to a wiring issue as if the relay or plugs are knackered then they are knackered and you would be getting the fault all the time.

Kenny

 

[paul73mt]

had the same thing and was the glowplug relay module. i checked the glow plugs myself just by measuring the resistance of the glow plugs all mine were below 1 Ohm.

Where are you based??? have a Star Machine here if you want to plug it in

 

[charlieboy2608]

What fault code is shown to prove its the glowplug relay module?

 

[paul73mt]

What fault code is shown to prove its the glowplug relay module?

No. All i had was it would come on as you started it up then go out but when you was driving it would come on every so often. They up rated it if you can see underneath it the base should be silver, if its black then its the old type.

 

[DrNick]

I never got around to sorting it out. It wasn't causing any issues in terms of starting and then I had the opportunity to get another car. So I sold the old one with full disclosure.

 

[zipdip]

Well one way to get rid of a glow plug problem sell the car,for most a cheap scanner will tell you which glow plug it is,if you run a V6 the plugs are numbered looking at the engine from the front 123 going back on the left side and then 456 going back on the right I had 5 go cost about £15 and 20 mins work.

 

[Markssl]

My experience of this issue....
When my GP light stayed on it was a glow plug issue. The car still started fine but I changed all plugs. A subsequent issue some years later was the GP light would go out as normal but the car wouldn't start from cold. After long cranking periods it would start. I assume the piston movement heated the engine. I Changed the GP relay and now it starts perfectly.


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[SteveFromAvantgarde]

I would check the fault codes first...it might just need 1 plug.