Drowned ECU's

mileshawk56 · 19th November 2018, 10:22

Any of you knowledge able types know why ECU's are not waterproof/proofed? Not my problem but my baby brothers- he is a MB owner and his German machine has just broken down on a journey in France and the MB agents have diagnosed a drowned ECU. Sorry if its a silly question but seems common sense?? Chris S.

selwol · 19th November 2018, 11:08

saves a few pennies on each car.. or when the car is new they don't let water in but as they get older gaps occur, pipes block and you get leaks.

BigRuss · 19th November 2018, 11:27

The 1.8 and V6 models of our cars do have a sealed ECU, unfortunately the Diesel ECU'S have an atmospheric pressure sensor inside them so they're not sealed.

Due to the poor design of the location of the wiring that goes into the bottom of the plastic box the diesel ECU fits into it allows water to enter it and the ECU.

This can also affect the Glow plug relay that's also contained in the same box.

Not sure about the Mercedes ECU's and their location though as I don't really get to work on them, but it may be similar.

Russ

selwol · 19th November 2018, 11:34

my sons merc had it under a cover in the passenger side footwell so electrical gremlins aplenty..

Avulon · 19th November 2018, 12:03

Quote:

Originally Posted by BigRuss

The 1.8 and V6 models of our cars do have a sealed ECU, unfortunately the Diesel ECU'S have an atmospheric pressure sensor inside them so they're not sealed.

Due to the poor design of the location of the wiring that goes into the bottom of the plastic box the diesel ECU fits into it allows water to enter it and the ECU.

This can also affect the Glow plug relay that's also contained in the same box.

Not sure about the Mercedes ECU's and their location though as I don't really get to work on them, but it may be similar.

Russ

Didn't know before the rationale for not having a sealed ECU on the diesel.

It is a garbage reason - You could still have it sealed and still sense atmospheric pressure - the case only needs a tiny bit of ability flex (well technically - change volume by an extremely small amount).

BigRuss · 19th November 2018, 12:57

Quote:

Originally Posted by Avulon

Didn't know before the rationale for not having a sealed ECU on the diesel.

It is a garbage reason - You could still have it sealed and still sense atmospheric pressure - the case only needs a tiny bit of ability flex (well technically - change volume by an extremely small amount).

Yes I know it is pretty rubblish, they could have fitted a vent with a diaphragm in that would have worked.

The thing is on other vehicle applications that use the same ECU they don't need to be sealed as they're in a location that doesn't get wet (unless the car gets totally submerged)

coab · 19th November 2018, 13:00

My old BMW 320D had a drowned ecu it was a 2007 model.

It was goosed and even marinabrian condemned it!

stevestrat · 19th November 2018, 13:05

Quote:

Originally Posted by BigRuss

Yes I know it is pretty rubblish, they could have fitted a vent with a diaphragm in that would have worked.

Of course you know why they didn't go for that option, more expensive.

Mike Noc · 19th November 2018, 15:51

Quote:

Originally Posted by BigRuss

The thing is on other vehicle applications that use the same ECU they don't need to be sealed as they're in a location that doesn't get wet (unless the car gets totally submerged)

Yes they did a far better job fitting it into the Freelander TD4 - nice and dry in a box in the engine bay.

And so high up you would have abandoned ship long before the water started lapping against it.

phatfiesta75 · 19th November 2018, 16:35

Hmm.....Yeah it is in a stupid place 😒 but is it not possible to reposition elsewhere on the car or is it far to much hassle?.
Ste

19th November 2018, 10:22	#1
mileshawk56 Posted a thing or two MGZT Join Date: Jul 2015 Location: Berkshire Posts: 1,280 Thanks: 1,738 Thanked 299 Times in 216 Posts	Drowned ECU's Any of you knowledge able types know why ECU's are not waterproof/proofed? Not my problem but my baby brothers- he is a MB owner and his German machine has just broken down on a journey in France and the MB agents have diagnosed a drowned ECU. Sorry if its a silly question but seems common sense?? Chris S.

19th November 2018, 11:27	#3
BigRuss Premium Trader 75 CDT Tourer,2.5 Launch Saloon, Omipro MG/Rover (T4) Join Date: Jul 2007 Location: Liversedge, West Yorkshire Posts: 5,405 Thanks: 1,105 Thanked 1,340 Times in 661 Posts	The 1.8 and V6 models of our cars do have a sealed ECU, unfortunately the Diesel ECU'S have an atmospheric pressure sensor inside them so they're not sealed. Due to the poor design of the location of the wiring that goes into the bottom of the plastic box the diesel ECU fits into it allows water to enter it and the ECU. This can also affect the Glow plug relay that's also contained in the same box. Not sure about the Mercedes ECU's and their location though as I don't really get to work on them, but it may be similar. Russ __________________ Replacement Key Service http://https://the75andztclub.co.uk/...d.php?t=244732 Full T4 Testbook diagnostics available. Diesel ECU repair and replacement. Options enabled or disabled as required. Diesel X-Power 135 and 160bhp, Rover 1.8T 150 to 160 MG 160 V6 to 177 upgrades available P.M. for details.

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19th November 2018, 11:08	#2
selwol Regular poster exrover75 saloon owner gone to a good home Join Date: Aug 2011 Location: rainford Posts: 71 Thanks: 6 Thanked 26 Times in 22 Posts	saves a few pennies on each car.. or when the car is new they don't let water in but as they get older gaps occur, pipes block and you get leaks.

19th November 2018, 11:34	#4
selwol Regular poster exrover75 saloon owner gone to a good home Join Date: Aug 2011 Location: rainford Posts: 71 Thanks: 6 Thanked 26 Times in 22 Posts	my sons merc had it under a cover in the passenger side footwell so electrical gremlins aplenty..

19th November 2018, 13:00	#7
coab This is my second home 2007 57 GOLF GTi EDITION 30 DSG Join Date: Nov 2011 Location: Newport Shropshire and Coventry. Posts: 5,137 Thanks: 2,424 Thanked 1,452 Times in 852 Posts	My old BMW 320D had a drowned ecu it was a 2007 model. It was goosed and even marinabrian condemned it!

19th November 2018, 16:35	#10
phatfiesta75 Loves to post rover 75 2.0 cdti connoisseur se Join Date: Nov 2010 Location: warrington Posts: 475 Thanks: 223 Thanked 91 Times in 85 Posts	Hmm.....Yeah it is in a stupid place 😒 but is it not possible to reposition elsewhere on the car or is it far to much hassle?. Ste