2005 W211 e270 glow plug light on permanently
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2005 e270 w211
2005 W211 e270 glow plug light on permanently
The glow plug light on dash has been on permanently ever since I bought the car. The car starts fine but I thought I’d try to solve the issue with the light staying on
i checked the resistance on the glow plugs. On all 5 plugs, 0.8 ohms. (Cheap multi meter)
check for breaks in cable between glow plug and relay, no issues there
check for 12v at glow plug when ignition on, no power to any plug
check for power to glow plug relay… brown wire earthed, white (and green I think) wire 0.5v - this doesn’t look right?
the cheapo code reader I bought off ebay gives code p0683 which sounds like a generic code
i don’t know but I would expect 12v to the relay (guessing from ecu?)
wthout a wiring diagram and expected pin out voltages I’m at the end of my diy knowledge and will give up now but thought I’d ask you guys if you had any ideas before I do
any ideas guys?
jim
i checked the resistance on the glow plugs. On all 5 plugs, 0.8 ohms. (Cheap multi meter)
check for breaks in cable between glow plug and relay, no issues there
check for 12v at glow plug when ignition on, no power to any plug
check for power to glow plug relay… brown wire earthed, white (and green I think) wire 0.5v - this doesn’t look right?
the cheapo code reader I bought off ebay gives code p0683 which sounds like a generic code
i don’t know but I would expect 12v to the relay (guessing from ecu?)
wthout a wiring diagram and expected pin out voltages I’m at the end of my diy knowledge and will give up now but thought I’d ask you guys if you had any ideas before I do
any ideas guys?
jim
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Joined: Feb 2018
Posts: 227
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CL500, W212 e350 mega-spec
Did you fix this? I tested very similar while chasing the same issue and I wonder if you got to the bottom of it. I see about 1.2v to the green/white wire and I wonder if that should be 12v.
The error message on the laptop diagnostics is: 2537-002 check component n14/2 (glow output stage). Short circuit to ground
The following diagnostics steps are very vague and you have to be familiar with the terminology used to be able to follow what they're saying. It seems to say check voltages and should see 11-14v but it is extremely unclear about which pin should have that level of voltage. If it means the small green / white wire should be showing 11-14 volts then that's my issue as it's only showing a very low voltage.
I'd be interested to hear whether or not you resolved this.
The error message on the laptop diagnostics is: 2537-002 check component n14/2 (glow output stage). Short circuit to ground
The following diagnostics steps are very vague and you have to be familiar with the terminology used to be able to follow what they're saying. It seems to say check voltages and should see 11-14v but it is extremely unclear about which pin should have that level of voltage. If it means the small green / white wire should be showing 11-14 volts then that's my issue as it's only showing a very low voltage.
I'd be interested to hear whether or not you resolved this.
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Joined: Feb 2018
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CL500, W212 e350 mega-spec
Traced this wire back to the ECU. It terminates at the ECU pin 43 on the F connector. Measuring at the ECU I still get the same low voltage. So it's not the wire running down to the glow plug relay. It must be something else.
Here's a question nobody can answer... what controls the voltage output on pin 43 of the ECU F connector. Is it temperature controlled to turn the glow plug relay on and off?
Here's a question nobody can answer... what controls the voltage output on pin 43 of the ECU F connector. Is it temperature controlled to turn the glow plug relay on and off?
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2005 e270 w211
Hi,
Nope, still have the issue. I see you’ve traced the gap relay wire to the ECU, great work! I don’t understand why there’s low voltage into the relay, should the voltage vary? I read that if a glow pug fails, it can cause the light on the dash to come on so how is the gp relay signalling to the ecu that’s there’s a fault? Theres only 2 wires into the glow pug relay if I recall?
it’s beyond my knowledge and expertise, and the car always starts even on very cold days so I left it…
good luck, hope you find the fix!
Nope, still have the issue. I see you’ve traced the gap relay wire to the ECU, great work! I don’t understand why there’s low voltage into the relay, should the voltage vary? I read that if a glow pug fails, it can cause the light on the dash to come on so how is the gp relay signalling to the ecu that’s there’s a fault? Theres only 2 wires into the glow pug relay if I recall?
it’s beyond my knowledge and expertise, and the car always starts even on very cold days so I left it…
good luck, hope you find the fix!
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Joined: Feb 2018
Posts: 227
Likes: 55
CL500, W212 e350 mega-spec
I'd be interested to know if the electronic boost control valve is causing any problem on your car?
Yes, someone responded to my main post on this issue saying they had a failed glow plug causing a similar problem. So I'll be checking my glow plugs next.
At a guess with the 'relay' circuitry being more than 'just a relay' it's probably fair to assume there is some kind of logic in there which can tell how much current is being drawn on each pin for each glow plug. Then if the system does an initial check at start up (you see the light go off briefly?) and one of the plugs is pulling maximum due to short circuit then it'll disable the system and you get the 1.25v output from the ECU to the relay.... it's a guess. Until I diagnose the glow plugs I won't know whether or not that all makes sense.
Yes, someone responded to my main post on this issue saying they had a failed glow plug causing a similar problem. So I'll be checking my glow plugs next.
At a guess with the 'relay' circuitry being more than 'just a relay' it's probably fair to assume there is some kind of logic in there which can tell how much current is being drawn on each pin for each glow plug. Then if the system does an initial check at start up (you see the light go off briefly?) and one of the plugs is pulling maximum due to short circuit then it'll disable the system and you get the 1.25v output from the ECU to the relay.... it's a guess. Until I diagnose the glow plugs I won't know whether or not that all makes sense.
Last edited by ejenner; Jan 4, 2023 at 06:43 AM.
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CL500, W212 e350 mega-spec
Update: fixed. My glow plug light has finally been turned off.
The problem was a faulty ECU. I tested and replaced every other part of the glow plug system so it left the ECU as the only remaining possibility. It's something which is really unlikely to happen, but it did.
If it is the ECU then that's a major issue as a replacement ECU won't start the car as a straight swap, you have to somehow fix the immobiliser so the car will start with a replacement ECU.
https://mbworld.org/forums/e-class-w...tem-issue.html
The problem was a faulty ECU. I tested and replaced every other part of the glow plug system so it left the ECU as the only remaining possibility. It's something which is really unlikely to happen, but it did.
If it is the ECU then that's a major issue as a replacement ECU won't start the car as a straight swap, you have to somehow fix the immobiliser so the car will start with a replacement ECU.
https://mbworld.org/forums/e-class-w...tem-issue.html
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