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Discussion Starter #1
Since the Glow Plug controller seems to cause so many glow plug CEL's and is such a bitch to replace, does anyone offer a harness extension to relocate the controller to a different location for easier access?

Thanks,
 

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Nuclear engineer
02/2012 X5 35d M57Y CPO 98K miles NOKIAN WR G3 12K miles
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I am nearing 100K miles at eight years in service, on the original preheat module and glow plugs.

Don***8217;t fix what ain***8217;t broke lest one fix until ***8216;broke***8217;.
 

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I am surprised a "harness extender kit" hasn't been put together.

oh, and yes mine is "broke" so I will fix it. I am at 107k miles and so its probably due for an intake de-carbon too. I just got the replacement parts in and planning out the work. If I could relocate the preheat module, now is the time to do it. I assume it is just the controller, but I will be replacing all the glow plugs now too.

Paul
 

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Nuclear engineer
02/2012 X5 35d M57Y CPO 98K miles NOKIAN WR G3 12K miles
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Reconsider "de-carbon". M57TU aren't notorious for CBU as other diesel motors are. Don't fix what ain't broke lest you fix until 'broke'.

My VW TDI went 180K miles on the same traditional GP. BMW E70 GP run perhaps 1% as long - low mass similar power. (Somebody***8217;s law. A human radiates ~250 wats and if the surface area was reduced to that of a incandescent filament, it would glow.)
 

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Discussion Starter #5
It is strange how the same manufacturer (Bosch) can get 200+ miles in one make and 50% less miles in another. My 04 PD TDI has 233K miles on the GP's. The only codes that car has ever thrown are for the EGR cooler - twice replaced under recall. I very early switched to Rotella T6 on that car and avoided the Camshaft failure known to be a problem following the Dealers oil rec.

Anyway, my E70 shows GP failure Cyl 1. This started last September. Through the winter I definitely had a cylinder not lighting off during cold starts. Whether it is the controller or the GP, I don't know. But I am not about tackle the repair without replacing all 6 and the module.

This X5 is without a doubt the most troublesome vehicle I have ever owned. I think my record is 15k miles without a CEL. 80% have been SCR/NoX related...
 

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Nuclear engineer
02/2012 X5 35d M57Y CPO 98K miles NOKIAN WR G3 12K miles
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Yes, the E70 is as complicated a vehicle as I expect to own with many possible independent failures. It has automotive systems of which I had never before heard, that took lots of study to begin to grasp.

The glow plugs then and now are very different as they evolve to require less and less power. The TDI did everything possible to conserve battery starting power, and the BMW approaches the same objective differently.

I believe that the secret to reliability and easy troubleshooting is to not let the DTC's accumulate and compound, but also to not fix what ain't broke for the risk of consequent damage.
 

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I am surprised a "harness extender kit" hasn't been put together.

oh, and yes mine is "broke" so I will fix it. I am at 107k miles and so its probably due for an intake de-carbon too. I just got the replacement parts in and planning out the work. If I could relocate the preheat module, now is the time to do it. I assume it is just the controller, but I will be replacing all the glow plugs now too.

Paul
The controllers go bad often. Glow plugs themselves are pretty reliable and can break off when being removed. Just change the controller and your code will probably go away. See the video below on controller replacement with the intake in place. I don't think anyone has had a controller go bad twice so extension harnesses will never be made.

And your CBU is fine. CBU us a 335d issue. I had moderate CBU because of an EGR recall issue and once the CBU was removed, I noticed zero difference in power or MPGs.

https://www.youtube.com/watch?v=dXGnK8UVTF0
 

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Discussion Starter #8
I tried the method in the video to change the controller without the intake removed. Either my hands are too big, or the 335d and the E70 have some differences. I couldn't get to it.

So whats up with removing the coolant pipe? It seems that is avoided when it appears to be the easiest method to get at the controller. Is it correct that the coolant system won't self purge any air?
 

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Nuclear engineer
02/2012 X5 35d M57Y CPO 98K miles NOKIAN WR G3 12K miles
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Removing and installing/replacing preheating control unit (M57T2)

No mention of removing a coolant pipe.

https://www.newtis.info/tisv2/a/en/e70-x5-xdrive35d-sav_201202/repair-manuals/12-engine-electrical-system/12-21-preheating-relay/1VnXOz13ih

Necessary preliminary tasks:
Read out fault memory of the DDE control unit, work through test plans if necessary.
Switch off ignition.
Disconnect battery negative lead.
Remove acoustic cover
35dX only:
Remove intake port.


Release positive battery cable (3) from bracket.
Detach fuel delivery line (1) from bracket.
Detach fuel return line (4) from bracket.
Release screw (2).
Tightening torque 11 13 4AZ.

Unlock plug connection (1) and pull off.
Unlock plug connector (3) and pull off.
Unscrew nuts (2).
Remove preheating relay (4).
Note:
Shown without coolant hoses for purposes of clarity.
 

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I removed the manifold and coolant pipe when I did mine. The diesel is self purging for coolant
 

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I tried the method in the video to change the controller without the intake removed. Either my hands are too big, or the 335d and the E70 have some differences. I couldn't get to it.

So whats up with removing the coolant pipe? It seems that is avoided when it appears to be the easiest method to get at the controller. Is it correct that the coolant system won't self purge any air?
I recently replaced the glow plugs and controller, and needed to remove both the intake and coolant pipe.

A fluid extractor (repurposed Harbor Freight brake bleeder) removed coolant from the expansion tank, so no mess when disconnecting coolant pipe.
 

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Discussion Starter #13
I removed the manifold and coolant pipe when I did mine. The diesel is self purging for coolant
Dragon dude, how much coolant did you lose? I wouldn't need more than a 1/2 gallon, would i?

I better check my engine operating temps too...T-stat time also?

Thanks, Paul
 

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Discussion Starter #14
I recently replaced the glow plugs and controller, and needed to remove both the intake and coolant pipe.

A fluid extractor (repurposed Harbor Freight brake bleeder) removed coolant from the expansion tank, so no mess when disconnecting coolant pipe.
good call, I have an extractor too.
 

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Dragon dude, how much coolant did you lose? I wouldn't need more than a 1/2 gallon, would i?

I better check my engine operating temps too...T-stat time also?

Thanks, Paul
Don't remember, but I did have add the OE BMW coolant (less than 1/2 gallon)
 

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I tried the method in the video to change the controller without the intake removed. Either my hands are too big, or the 335d and the E70 have some differences. I couldn't get to it.

So whats up with removing the coolant pipe? It seems that is avoided when it appears to be the easiest method to get at the controller. Is it correct that the coolant system won't self purge any air?
I did not remove a coolant pipe when replacing with the intake in place. I did loosen some of the pipe retaining clamps/clips go get a better view. 335d is slightly different but those hoses can be pulled to the side to complete the process as done in the video.

Big hands are an asset and a liability. It will be harder to get them all the way back there. But once there, you will have more strength to squeeze and release the electrical connectors.
 
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