[Yesss]

Hi All,

I am having a heap of garbage alarms (Fault in Drive, DSC fail, DBC fault, Flat tyre monitor, Fuel pump, Cruise control failure) come up intermittently when I try start my E90 320D N4720D VIN A472613.

Vehicle is stock with exception of EGR delete and swirl flap delete.
In nice weather in Australia, so no temp, water, ice problems. (No corrosion or water in DDE box, etc)
Vehicle is fairly well maintained with me doing basics to keep it alive. (Fluids, filters, brakes, etc...)

I have a basic OBD scanner to clear alarms and see values.

I did a few things like, new battery, fuel filter, glow plugs, swirl flap delete.
I have checked every fuse I can find and have tested the relays in the DDE box, all good.

Starter and battery are strong and crank like crazy, but with all of the DDE/fuel faults it just winds over.

I have read a few similar faults from years ago, but no clear resolution that would help me.

What I am finding is I can scan each of the modules normally, but when the faults come up on a failed start I can't scan the DDE module (Communication error)

The frustrating thing is that it is intermittent, some times it starts and drives beautifully, then sometimes it doesn't start and just throws up a heap of nonsense alarms that are probably linked to a DDE or communication issue.
(Don't even have tyre pressure monitor, but get the alarm)

Any thoughts would be great.
My next step is to maybe buy a second hand DDE and get it coded to my car and see if it is that, but I would rather not if I don't have to.

Thanks in advance.

[N52bigblock]

Have you checked all your engine earth straps?? Shouldn't be an issue in Aussie but definitely worth checking. I would also get the correct wiring diagram for your car and check the earths for the DDE

[N52bigblock]

Here's the link for the wiring diagram. https://www.newtis.info/tisv2/a/en/e...supply/kXBztdw The earth point for the DDE is under the bonnet on the l/h side, just in front of the strut tower. Heres a link to the location.
It is called X165 https://www.newtis.info/tisv2/a/en/e...904/1VnXZionJR Check that the earth point is clean and tight. I would also put a new DDE relay in it. Don't fuck around with it, just go to BMW and get a new one. About $30-$40 from memory. While you are replacing the relay, have a good look at the relay connections and wiring. Here's a link to DDE relay location. Its in the Ebox next to the DDE. The relay is called K2003a https://www.newtis.info/tisv2/a/en/e...00904/HOxL4khJ

I reckon it could just be the relay, but definitely check the earths as well.

[Yesss]

Sound good, will get a new relay and check earths. Cheers.

[Yesss]

Earths were all good. Replaced DDE relay ($40) and have had 20 plus successful starts.
Fingers crossed that what it was. Such an easy fix for a troublesome problem.
Thanks for your help.

[N52bigblock]

Originally Posted by Yesss

Earths were all good. Replaced DDE relay ($40) and have had 20 plus successful starts.
Fingers crossed that what it was. Such an easy fix for a troublesome problem.
Thanks for your help.

No worries mate. Glad to help