# Glow plug & exhaust sensor issues



## diesel fan123 (Nov 25, 2011)

Hi,
Coming up on 90k miles on the "d", SES came on, codes were:

Exhaust back pressure sensor against particulate filter
Code: 004D03

Cylinder 1 Control
Code: 004A6E

BMW replaced the glow plug in cylinder #1, and replaced the sensor for exhaust back pressure. 
CPO expires @ 100k, so I get to enjoy the torque monster for about 5-8k more miles, then move on to more mundane transportation.

Recently replaced the two Michelin Pilot fronts, worn out after 35k miles. No complaints, great tires.

The only thing I miss from the original Conti-run flats was the burnouts.
The Conti rubber compound became so hard and slippery over time, I could light them up from a standing start
(computer management =off). Miss that part, the Michelins just dig in and provide full thrust.
Frank


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## Doug Huffman (Apr 25, 2015)

I watched a kid, an acquaintance back in the Sixties, try a 4WD burnout in his daddy's Suburban at the main intersection of San Jose, Calif. He dropped the front joint of the front driveshaft and damn near rolled it at 5 mph.


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## Flyingman (Sep 13, 2009)

diesel fan123 said:


> Hi,
> Coming up on 90k miles on the "d", SES came on, codes were:
> 
> Exhaust back pressure sensor against particulate filter
> ...


Did BMW cover the glow plug under extended warranty? They wouldn't for me, it is "excluded". I went ahead and replaced them all anyway. Figured they are very much like light bulbs, resistors that have a definitive lifetime.


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## Doug Huffman (Apr 25, 2015)

The Centennial Light Bulb has been burning for well over a hundred years and is often cited as evidence of planned obsolescence.


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## diesel fan123 (Nov 25, 2011)

Apparently the glow plug was covered under whatever the "Platinum" plan is, that I have.
The only charge I paid was a $50 deductible, as always.
Or they messed up my billing, in which case I may chose not to complain.


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## Flyingman (Sep 13, 2009)

The Centennial Light Bulb has been burning for well over a hundred years and is often cited as evidence of planned obsolescence.

Leave it to Doug! This actually exists.:yikes:

http://www.centennialbulb.org/


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## diesel fan123 (Nov 25, 2011)

This is baffling, these exact same codes came back today!

Exhaust back pressure sensor against particulate filter
Code: 004D03

Cylinder 1 Control
Code: 004A6E

Last two days the car has done a regen once each day too. 

They changed the glow plug and sensor a couple of weeks ago, and the car still thinks it has a bad #1 glow plug and sensor, I wonder if it might be another of those "diagnostic software is complaining, but can't actually identify the issue" gremlins ??
Frank


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## GreekboyD (Jan 25, 2012)

diesel fan123 said:


> This is baffling, these exact same codes came back today!
> 
> Exhaust back pressure sensor against particulate filter
> Code: 004D03
> ...


This will be your glow plug control unit for sure.

As for the first one, could be a few things related to your DPF.


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## diesel fan123 (Nov 25, 2011)

I have cleared the codes a couple of times, the only one that repeats is the glow plug.
I agree it is the relay control, but it's so hot here, I don't care if the glow plugs work or not, it starts fine.
Noticed a little roughness for the first few revolutions of the crank, then smooths out.
I'll take it in a couple months, (when I will have more free time) to have the relay replaced.


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## GreekboyD (Jan 25, 2012)

diesel fan123 said:


> I have cleared the codes a couple of times, the only one that repeats is the glow plug.
> I agree it is the relay control, but it's so hot here, I don't care if the glow plugs work or not, it starts fine.
> Noticed a little roughness for the first few revolutions of the crank, then smooths out.
> I'll take it in a couple months, (when I will have more free time) to have the relay replaced.


Yes you're right on all accounts. You're in a warm state so no big deal. Not sure if you have emissions tests there but if you do, this issue would cause the car to not pass the test.


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## toledo_335i_6 (Jul 13, 2015)

diesel fan123 said:


> I have cleared the codes a couple of times, the only one that repeats is the glow plug.
> I agree it is the relay control, but it's so hot here, I don't care if the glow plugs work or not, it starts fine.
> Noticed a little roughness for the first few revolutions of the crank, then smooths out.
> I'll take it in a couple months, (when I will have more free time) to have the relay replaced.


Did you end up resolving your issue? I have an intermittent error code showing up related to the DPF (004667) and I am suspect on the exhaust pressure sensor. Also have an error related to glow plugs (likely controller) so feels like a similar issue. Interested if you had fixed yours....

EDIT: (sorry i just realised you only posted this last week! the AU/US date format threw me... i thought you had posted this in January


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## diesel fan123 (Nov 25, 2011)

Took the car in again, as it had complained that the just replaced glow plug #1 was bad again. 
I told them that there is nothing wrong w/ the plug, the controller is bad.
They replaced the glow plug controller. 
No idea what the other sensor replacement was, but this car has so many sensors&#8230;&#8230;&#8230;.
Possibly it will start performing regens again, w/ this new sensor in place.


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## blue dragon (Aug 10, 2011)

The differential pressure sensor connects to the back and front of the DPF. The exhaust backpressure sensor connects to the exhaust manifold. Either one going bad will result in code 4d03. You need to run the test plan for both of them.


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