Glow plug codes
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Newbie
Joined: Mar 2017
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2007 W164 ML280
Glow plug codes
Hi
I have recently bought a 2007 W164, knowing it had a heater / glow plug issue of some sort. It had an unrelated scan on a STAR machine today for something else but 2 of the codes that came up were
2270-004 N14/3 (glow time output stage) at least one of the glow plugs is not actuated
2137-004 Glow plug cylinder 5 open circuit
Are these essentially the same fault and basically glow plug 5 is needing replacement, or could it be the relay or something? Or are these 2 separate issues?
Thanks.
I have recently bought a 2007 W164, knowing it had a heater / glow plug issue of some sort. It had an unrelated scan on a STAR machine today for something else but 2 of the codes that came up were
2270-004 N14/3 (glow time output stage) at least one of the glow plugs is not actuated
2137-004 Glow plug cylinder 5 open circuit
Are these essentially the same fault and basically glow plug 5 is needing replacement, or could it be the relay or something? Or are these 2 separate issues?
Thanks.
Senior Member
Joined: Aug 2009
Posts: 427
Likes: 57
13 GL350, 14 SL550
This is a tricky problem to fix.
The glow plug controllers fail over time, and start to report random problems.
So this means your problem can be one of two things:
a)the glow plug #5
b)glow plug relay/controller itself
One easy way to tell is find the relay itself (it's on the front of the engine, just slightly to the left of center (by a few inches) if you're standing facing the engine. Look up a new one and you'll see what it looks like.
There is an old style (metal and I believe it's held together with screw heads) and a plastic (all one piece) unit. The plastic is newer. Metal ones must leak water as they eventually fail.
First see if it's metal... if so, replace it because it's easier than swapping a glow plug. If that doesn't fix the problem, at least know that you have the most recent version now as the old one would have failed eventually. Then replace the glow plug if required.
It's held on by 2 nuts I believe (don't drop them!) and a harness plug. Just unbolt, unplug, and swap.
Make sure you are replacing with the most updated part # (so buy from a dealer or at least ensure you're getting the latest revision if you buy online). There were I believe 4 revisions of this part. .. they obviously keep updating it for a reason.
My controller failed 2-3 years ago, and never a problem since replacing it. Have never touched the glow plugs themselves. There is an ohm test for the plugs if you really want to dig it up online, you can do that to verify before replacing the controller. But sometimes the plugs test OK even when dying (because they aren't fully dead). So I'd just replace the controller/relay.
The glow plug controllers fail over time, and start to report random problems.
So this means your problem can be one of two things:
a)the glow plug #5
b)glow plug relay/controller itself
One easy way to tell is find the relay itself (it's on the front of the engine, just slightly to the left of center (by a few inches) if you're standing facing the engine. Look up a new one and you'll see what it looks like.
There is an old style (metal and I believe it's held together with screw heads) and a plastic (all one piece) unit. The plastic is newer. Metal ones must leak water as they eventually fail.
First see if it's metal... if so, replace it because it's easier than swapping a glow plug. If that doesn't fix the problem, at least know that you have the most recent version now as the old one would have failed eventually. Then replace the glow plug if required.
It's held on by 2 nuts I believe (don't drop them!) and a harness plug. Just unbolt, unplug, and swap.
Make sure you are replacing with the most updated part # (so buy from a dealer or at least ensure you're getting the latest revision if you buy online). There were I believe 4 revisions of this part. .. they obviously keep updating it for a reason.
My controller failed 2-3 years ago, and never a problem since replacing it. Have never touched the glow plugs themselves. There is an ohm test for the plugs if you really want to dig it up online, you can do that to verify before replacing the controller. But sometimes the plugs test OK even when dying (because they aren't fully dead). So I'd just replace the controller/relay.
Junior Member
Joined: Jan 2008
Posts: 68
Likes: 0
2007 ML320 CDI
This is a tricky problem to fix.
The glow plug controllers fail over time, and start to report random problems.
So this means your problem can be one of two things:
a)the glow plug #5
b)glow plug relay/controller itself
One easy way to tell is find the relay itself (it's on the front of the engine, just slightly to the left of center (by a few inches) if you're standing facing the engine. Look up a new one and you'll see what it looks like.
There is an old style (metal and I believe it's held together with screw heads) and a plastic (all one piece) unit. The plastic is newer. Metal ones must leak water as they eventually fail.
First see if it's metal... if so, replace it because it's easier than swapping a glow plug. If that doesn't fix the problem, at least know that you have the most recent version now as the old one would have failed eventually. Then replace the glow plug if required.
It's held on by 2 nuts I believe (don't drop them!) and a harness plug. Just unbolt, unplug, and swap.
Make sure you are replacing with the most updated part # (so buy from a dealer or at least ensure you're getting the latest revision if you buy online). There were I believe 4 revisions of this part. .. they obviously keep updating it for a reason.
My controller failed 2-3 years ago, and never a problem since replacing it. Have never touched the glow plugs themselves. There is an ohm test for the plugs if you really want to dig it up online, you can do that to verify before replacing the controller. But sometimes the plugs test OK even when dying (because they aren't fully dead). So I'd just replace the controller/relay.
The glow plug controllers fail over time, and start to report random problems.
So this means your problem can be one of two things:
a)the glow plug #5
b)glow plug relay/controller itself
One easy way to tell is find the relay itself (it's on the front of the engine, just slightly to the left of center (by a few inches) if you're standing facing the engine. Look up a new one and you'll see what it looks like.
There is an old style (metal and I believe it's held together with screw heads) and a plastic (all one piece) unit. The plastic is newer. Metal ones must leak water as they eventually fail.
First see if it's metal... if so, replace it because it's easier than swapping a glow plug. If that doesn't fix the problem, at least know that you have the most recent version now as the old one would have failed eventually. Then replace the glow plug if required.
It's held on by 2 nuts I believe (don't drop them!) and a harness plug. Just unbolt, unplug, and swap.
Make sure you are replacing with the most updated part # (so buy from a dealer or at least ensure you're getting the latest revision if you buy online). There were I believe 4 revisions of this part. .. they obviously keep updating it for a reason.
My controller failed 2-3 years ago, and never a problem since replacing it. Have never touched the glow plugs themselves. There is an ohm test for the plugs if you really want to dig it up online, you can do that to verify before replacing the controller. But sometimes the plugs test OK even when dying (because they aren't fully dead). So I'd just replace the controller/relay.
Very helpful for me because I'm pulling a cylinder 1 glow plug error too. Will probably order/buy a new relay and controller box and replace those first as you stated.
Could replace all of it for less than dealer diagnostic!
Senior Member
Joined: Aug 2009
Posts: 427
Likes: 57
13 GL350, 14 SL550
That changes things.. if you are getting errors on two different glow plugs then I'm 95%+ certain that it is the controller. Very rare for two plugs to go bad at the same time.
This appears to be the most recent part. Mine was replaced in fall 2014 and was part #5701. So 7701 is definitely a newer version. I guess they updated it yet again!
http://www.genuinemercedesparts.com/...nit-6429007701
There are Beru and other ones on eBay but I'd buy the genuine latest version one to be safe. The ones on eBay may be fine, or they could be copies of older versions which you don't want.
My truck has 180,000 mi and has all six original glow plugs with no errors, if that gives you a reference point. Maybe that isn't common, but just saying the controller/relay failed somewhere around 125-150k miles and the plugs are still good to this day.
This appears to be the most recent part. Mine was replaced in fall 2014 and was part #5701. So 7701 is definitely a newer version. I guess they updated it yet again!
http://www.genuinemercedesparts.com/...nit-6429007701
There are Beru and other ones on eBay but I'd buy the genuine latest version one to be safe. The ones on eBay may be fine, or they could be copies of older versions which you don't want.
My truck has 180,000 mi and has all six original glow plugs with no errors, if that gives you a reference point. Maybe that isn't common, but just saying the controller/relay failed somewhere around 125-150k miles and the plugs are still good to this day.
Junior Member
Joined: Jan 2008
Posts: 68
Likes: 0
2007 ML320 CDI
That changes things.. if you are getting errors on two different glow plugs then I'm 95%+ certain that it is the controller. Very rare for two plugs to go bad at the same time.
This appears to be the most recent part. Mine was replaced in fall 2014 and was part #5701. So 7701 is definitely a newer version. I guess they updated it yet again!
http://www.genuinemercedesparts.com/...nit-6429007701
There are Beru and other ones on eBay but I'd buy the genuine latest version one to be safe. The ones on eBay may be fine, or they could be copies of older versions which you don't want.
My truck has 180,000 mi and has all six original glow plugs with no errors, if that gives you a reference point. Maybe that isn't common, but just saying the controller/relay failed somewhere around 125-150k miles and the plugs are still good to this day.
This appears to be the most recent part. Mine was replaced in fall 2014 and was part #5701. So 7701 is definitely a newer version. I guess they updated it yet again!
http://www.genuinemercedesparts.com/...nit-6429007701
There are Beru and other ones on eBay but I'd buy the genuine latest version one to be safe. The ones on eBay may be fine, or they could be copies of older versions which you don't want.
My truck has 180,000 mi and has all six original glow plugs with no errors, if that gives you a reference point. Maybe that isn't common, but just saying the controller/relay failed somewhere around 125-150k miles and the plugs are still good to this day.
