DDE Diesel Electronics modules

coopersim · 01-07-2013, 03:58 PM

I've had a rough idle at start-up issue for a while now, I've got the codes off the car, and it's showing:

4252 DDE: Glow plug, cylinder 5, activation - Open Circuit - Fault currently present - fault would......... (then it goes off the edge of the screen)

Would one faulty glow plug cause such uneven idling?

Also, I can't seem to access any of the three DDE Diesel Electronic modules listed in DIS to be able to interrogate the system further, any idea why this is?

Cloud1515 · 01-07-2013, 05:42 PM

Faulty glow plugs can cause uneven idling but only for a few seconds after cold start.

coopersim · 01-07-2013, 05:50 PM

Only one out of 6 though?

Elliott@DetailAddict · 01-07-2013, 06:19 PM

Yes. Just like 1 faulty spark plug can cause a rough idle or misfire for gassers.

hugus311 · 01-07-2013, 07:47 PM

Quote:

Originally Posted by Grant@DetailAddict

Yes. Just like 1 faulty spark plug can cause a rough idle or misfire for gassers.

But unlike spark plugs which are constantly being ran when vehicle is on, glow plugs are only used to heat up the chamber and then not used again until you re turn on a cold car. So a bad glow plug will cause even idle ing but only until fully warmed

Elliott@DetailAddict · 01-08-2013, 11:38 AM

I understand that.
I was equating how just one can cause the idle to be rough just like only 1 spark plug can do that to gassers.

4EST · 01-08-2013, 02:29 PM

you would hardly notice 1 bad glow plug. Even with 3/6 glow plugs malfunctioning your car could start perfectly up to ~-15C
My older E46 had busted relay (so 4/4 glow plugs were not working), and at ~-20C it would crank ~3 sec more.

if you have rough idle, then look more to injectors and air intake

you might be needing ICOM or ICOM emulator to access DDE with ISID

01-07-2013, 03:58 PM	#1
coopersim Captain 77 Rep 879 Posts Drives: 420d Join Date: Apr 2009 Location: Glos. iTrader: (2)	DDE Diesel Electronics modules I've had a rough idle at start-up issue for a while now, I've got the codes off the car, and it's showing: 4252 DDE: Glow plug, cylinder 5, activation - Open Circuit - Fault currently present - fault would......... (then it goes off the edge of the screen) Would one faulty glow plug cause such uneven idling? Also, I can't seem to access any of the three DDE Diesel Electronic modules listed in DIS to be able to interrogate the system further, any idea why this is?
	Appreciate 0 Tweet Quote

01-07-2013, 05:42 PM	#2
Cloud1515 Autobahnraser 0 Rep 7 Posts Drives: 2008 e92 325d Join Date: Sep 2012 Location: Germany iTrader: (0)	Faulty glow plugs can cause uneven idling but only for a few seconds after cold start.
	Appreciate 0 Quote

01-07-2013, 05:50 PM	#3
coopersim Captain 77 Rep 879 Posts Drives: 420d Join Date: Apr 2009 Location: Glos. iTrader: (2)	Only one out of 6 though?
	Appreciate 0 Quote

01-07-2013, 06:19 PM	#4
Elliott@DetailAddict Brigadier General 300 Rep 4,444 Posts Drives: E90 Join Date: May 2011 Location: Santa Clara, CA iTrader: (0)	Yes. Just like 1 faulty spark plug can cause a rough idle or misfire for gassers.
	Appreciate 0 Quote

01-08-2013, 11:38 AM	#6
Elliott@DetailAddict Brigadier General 300 Rep 4,444 Posts Drives: E90 Join Date: May 2011 Location: Santa Clara, CA iTrader: (0)	I understand that. I was equating how just one can cause the idle to be rough just like only 1 spark plug can do that to gassers.
	Appreciate 0 Quote

01-08-2013, 02:29 PM	#7
4EST Private 6 Rep 97 Posts Drives: E90 320d LCI Join Date: Oct 2012 Location: Brasov, RO iTrader: (0)	you would hardly notice 1 bad glow plug. Even with 3/6 glow plugs malfunctioning your car could start perfectly up to ~-15C My older E46 had busted relay (so 4/4 glow plugs were not working), and at ~-20C it would crank ~3 sec more. if you have rough idle, then look more to injectors and air intake you might be needing ICOM or ICOM emulator to access DDE with ISID
	Appreciate 0 Quote