Rbrtmcnulty

Hi there I have a 2005 BMW e61 pre lci 535d
it's had a large front mount intercooler
Egr and cooler removed
Dpf and cat removed
Remapped
All vac lines been replaced
new pressure converters
I have two engine codes come up
4156 dde exhaust flap actuator activation
46d1 dde control unit internal 4
Please could somebody through some suggestions out there on what to try please

donpb

Specifically describe no boost under 3k.

Rbrtmcnulty

The car is dead under 3k on diagnostic watching the actual and specified boost readings on idle it's siting around 1000 mbar which is atmospheric pressure when you rev the car up but under the 3k ish mark the pressure actually drops to around 900-950 mbar and slowly creeps back up to the 1000 mark again when it's specified boost is wanting around 1500 mbar

donpb

You've done a ton of rework; did it ever run per specification while you've owned it?

Rbrtmcnulty

No I bought as a project to be honest bud so I've never actually had it running correctly and I've spent allot of time and money trying to rectify the problem new actuator new pressure converter new small turbo all new vac lines and I'm just stumped now

donpb

I was thinking the mapping could be the culprit, but @seanjordan20 would know more about that than myself. I don't do mapping or coding at all.

seanjordan20

You have an internal fault to a module so nothing you tried would of fixed it. You need to pull your DDE and look for oxidation. Could be on the plugs ( what you're hoping for) or could be water penetrated the module and the board is oxidized. If that's the case and you're not good at repairing boards then you'll have to send it off for repair. This is what I'm seeing is your main issue by having the 46D1 error. It would cause the no boost issue. If that is the case and you get it fixed then you need to pull out the DDE box and clear the drain from debris. Water is not able to escape causing it to flood the box.

Rbrtmcnulty

When I first got the car it didn't have that 46d1 fault and still had no boost I've looked into the box where the dme is and haven't seen any water or trace of it but I haven't unpluged it I will do that today and post up some pictures one thing I did notice is that one of my pressure converters gets relly hot to touch even with the engine not running is that something you have heard of before

seanjordan20

Are they OEMs or aftermarket?

Rbrtmcnulty

I've just fitted a brand new BMW on the OEM website it is number 2 on the picture and other one is an aftermarket but it's the BMW one that was getting hot