Basic-ML320CDI

I have search online but have come up with nothing to help solve this issue.

I purchased the truck and have a receipt for new glow plugs and controller installed at an indy, as it has been getting colders, below -2 deg C the truck becomes hard to start. Yesterday at -9 deg C it would not start, sometimes fires once or twice then stop. If I plug the engine block heater in it will start right up once warmed.

I have fuel anti-gel additive in the gas as well as we should be on winter diesel here. I can hear the fuel pump running and recently installed a new fuel filter.

I suspected glow plugs even though they had been changed, sure enough they were the incorrect Bosch 4.4V not the required NGK 7V glow plugs, so I bought new ones from the dealer and installed them. I do have the correct glow plug controller (A 642 900 58 01) but wonder if it was damaged with the 4.4V glow plugs installed?

No CEL or OBD-II codes, the glow plug light on the dash would light up and go out in ~2 secs before I started it. It doesn't stay on longer or flash.

I think I will go get a new glow plug controller and install it to see if that fixes the problem, I hate to throw parts at it but for the cost and likelihood that it is the problem its worth the try.

Basic-ML320CDI

I fixed the problem, I replaced the glow plug controller with the correct one which is A 642 900 57 01, not 58 01 that is for the older style glow plugs.

I think my original problem was the glow plug controller but now I have the updated NGK 7V glow plugs and new controller so should be good for a long time.

Hopefully someone else will find this helpful.

-19 deg C and it fired right up.

Odd thing still was I had no check engine light or any codes.

bha

I replaced mine because it started giving an error code (bad glow module). Part number in EPC was shown as 57 01 so I ordered that one.


I did notice they listed TWO glow modules, both for 2007's. Depending on your VIN, they used 2 different modules that year so you need to know exactly which one you have.


You have to be careful going onto online parts sites and buying a "2007 GL320 CDI glow module" because that could be one of two part #'s.


I always look into EPC and find the exact one the truck was built with (or latest superceded part #) and then order exactly that part #.


Your issue isn't uncommon.. I did read of a few people replacing with the wrong module and it wouldn't work. It fits and looks proper and everything, just doesn't work. No error codes or anything.


Glad to hear you have it solved!

Basic-ML320CDI

I went to the dealer and they used my vin number, problem was they listed both types for my vehicle and the parts guy messed up telling me I needed 58 01 for the new ceramic glow plugs, so I though all I had was the wrong plugs.

57 01 is for the newer NGK ceramic plugs, 58 01 for the older steel plugs but I am not sure if they were both 7V or just the new NGK ones.

Mine had 4.4V bosch plugs which the part number was 0 250 403 008 (no mercedes part number on them) and they list for a sprinter van or jeep.

At least these are all easy to access and change, probably took me less then an hour to swap all the glow plugs and controller.

Only thing needed that was a bit unusual is a deep 8mm socket for the glow plugs, and of course a E10 socket (an 8 mm socket seems to work as well if in a pinch).

Tips on removing the old plugs
-Make sure the engine is warm, which helps in removing the old glow plugs, turn them a touch tighter before removing them.
-Put ample anti seize on the new ones to make life nice next time.
-I also blew out the area around them with compressed air to remove the dirt.
-If you suspect they are going to be hard to remove try to soak them a few times with a quality penetrating spray before driving and warming the engine up.

You don't want them to break off...

poolmanEd

I think I have the same thing going on with my 2008 320/cdi. Was this a costly fix?

bha

Very easy fix. But you'll get a check engine light if this is actually the problem.


My understanding is as follows. Don't quote me on the code numbers but they follow the format I've outlined:


Code P0670 - Glow module is faulty
P0671 - Glow plug #1 faulty OR the glow module is bad
P0672 - Glow plug #2 (see above
(etc)


So basically the last digit tells which plug is faulty, but if you get a 0671-0676 it COULD also be the controller going bad and it's just telling you the plug is faulty.


So if you get P0670 replace the controller. If you get 0671-0676 it's your decision.. replace the module and hope that was the problem (easy fix but costly) or replace the plug and know that you might have replaced a good plug (cheap fix but more labour, and then you'll end up doing the module anyhow)


I got 0670 so replaced the module. Took 15 mins. 3 bolts and it's out.


Look on Youtube as there is a Jeep CRD where they replace it, and it's exactly the same on our trucks.


If you aren't getting any codes, I wouldn't start replacing things. You'll definitely know if a plug or module is gone bad as you'll get a check engine light. If no codes, you should be looking at other things like battery, etc.

Basic-ML320CDI

I DID NOT have any CEL or codes but had a problem. Was fixed with new glow plug controller.

I suspect (no proof as no info is available) there is a temperature sensor inside the glow plug module, and if it failed it thinks its warmer then it is. Which leads to no glow plug action or not enough, no code as it doesn't see anything wrong.

^just my guess

Online at various places parts are $200 for updated 57 01 glow plug controller and $80 for each NGK 7V ceramic glow plug.

Easy to do yourself, see above.

bha

Good point. I have now heard of a few people that have had similar problems (no error code but controller faulty). Apparently the 2007s were built with a version of the controller that will eventually fail for sure.


So maybe the best advice is this: if you're having glow problems, replace the module first then diagnose further.


Considering the controller can fail at any time, doesn't necessarily throw a code, and can actually tell you there is a glow plug problem when there isn't (and the module itself is at fault) I would say it's safer to just replace the module.


I also bought the updated module. It looks a lot different.. the original was metal and looked like water could eventually get into it. The new one is a solid piece of plastic and looks much sturdier. I'm pretty sure the new one will never fail.


So if you think you have a problem, replace the controller first.


By the way, I did hear of cheaper glow plugs. Someone mentioned on eBay that the kit was in the $100-150 range (for either Bosch or Beru, can't remember) and it's cheaper than buying one at a time. If I have to replace plugs, I might look into the kit.

poolmanEd

Problem solved by changing the module. No more check engine light.