[mace0]

Hey I have been having these weird issues with my VVT system that I can't seem to find the cause off. The errors are 2856, 286C. I have replaced all of the main parts given a lot of them were leaking any way (car is old). So i replaced the: cam shaft sensors, vanos, vvt servo motor and the eccentric shaft sensor. I later found that one of the non replaceable fuses on the battery distribution box was bust so I replaced the whole thing.

This did seem to fix some of the problem (the motor adjusts to the center position), but now my Eccentric Shaft sensor is showing 12.3 volts as its reference voltage (pic included). Before replacing the distribution box it came up as 2V. I'm not entirely sure what has cause this increase in voltage, and if this has damaged the sensor. The most obvious would be the distribution box, but its the same part number, and also I tested it before installing it. I have included pics with the errors and the read out from the ISTA-D. The truth is that the errors are stored in there, since fitting the new parts I haven't turned on the ignition. The valve cover is still off as I wanted to confirm for myself that the system was still working (having seen this being done in videos on youtube with the same engine, sealing up the valve cover isn't a job you want to keep on doing time and time again until you get it right). I say this as there is a chance that whatever the problem is, it isn't present any more. In other words once I start the ignition it may no longer go in to limp more. My only doubt of this comes from the fact the voltage of the ESS is showing as 12V. Hence why I wanted to get some answers before taking that risk. Car is a 2008 320i E90 with an n46b20b.

Thanks for any help.

[PichaDis11]

It seem the N46 uses the same Servo motor as the N52 for the Valvetronic system. The motor should placed in service position to remove and be installed. When installed, have ISTA-D initialize the motor function to spec before starting the engine.

Fit everything back together before testing anything else. Checking the system with the Valve cover off is pointless as you'll always get those codes.

[mace0]

So would you be worried about the supply voltage, being 12.3V? Im wondering if the power distribution box has resistors instead of fuses (I read on a forum that it contained non replaceable fuses but this could be wrong and they could be resistors, should probably measure them next). And this is why its now reading 12.3V. Problem is its the right part number, but it was a second hand part so there is no way to know for sure if its the right one. Its the only thing I could think of.

Just for clarification the part I am talking about is: 10688710 Battery Fuse Control unit Junction Box is one of the names, and I guess that would mean it is a fuse box.

[Bimmer Pleaser]

Originally Posted by PichaDis11

It seem the N46 uses the same Servo motor as the N52 for the Valvetronic system. The motor should placed in service position to remove and be installed. When installed, have ISTA-D initialize the motor function to spec before starting the engine.

Fit everything back together before testing anything else. Checking the system with the Valve cover off is pointless as you'll always get those codes.

Unrelated to OP problem: I just replaced the valve cover gasket on my N52; have not turned it on yet because I am waiting on a bolt. I did not replace the serve or the sensor, just the gaskets. Should I do anything with the servo before turning on the car? As you know there is a little hole opposite the servo shaft where you can manually spin the servo.

[PichaDis11]

Originally Posted by mace0

So would you be worried about the supply voltage, being 12.3V? Im wondering if the power distribution box has resistors instead of fuses (I read on a forum that it contained non replaceable fuses but this could be wrong and they could be resistors, should probably measure them next). And this is why its now reading 12.3V. Problem is its the right part number, but it was a second hand part so there is no way to know for sure if its the right one. Its the only thing I could think of.

Just for clarification the part I am talking about is: 10688710 Battery Fuse Control unit Junction Box is one of the names, and I guess that would mean it is a fuse box.

While it may be alarming that the sensor is reporting an over voltage situation; it doesn't necessarily point to a faulty sensor. The sensor isn't actually present in the motor correctly as it is with the VC off VVT motor not present etc. Second hand part/ Now we are just in a guessing game if it works or not. ID rather get a new part and be done with it. The distribution box most likely are just fuses. All major circuits are fused from this panel.

Originally Posted by Bimmer Pleaser

Unrelated to OP problem: I just replaced the valve cover gasket on my N52; have not turned it on yet because I am waiting on a bolt. I did not replace the serve or the sensor, just the gaskets. Should I do anything with the servo before turning on the car? As you know there is a little hole opposite the servo shaft where you can manually spin the servo.

You'll need to place the servo motor in it's service mode as well. Use a hexagon socket wrench to manually turn it clockwise. There will be a pressure point. DO NOT turn the shaft pass that.

Installing as it is, you run the risk to damage the shaft that it should connect to. This happened to my car when I did the VC Change. Now every 3 weeks I get VVT code and stating sluggish movement.

[mace0]

Bumping this back up as the problem is still there. The car starts and drives ok, but the idle can be a little rough and you can tell its not all running 100%. The only problem I can see still is the supply voltage eccentric shaft sensor is still coming up as 12V (or more). Any ideas what might be causing the voltage to be so high? Had a read of some wiring information, is the lower, 5V supplied by the DME? Would that be a good place to start? Thanks for any info on the subject. Surprised there is not more info out there on this as it is one of the few values that the testing module gives you.

[mace0]

Anyone have any input?

My guess is on a short on the harness or possibly the DME is damaged. I read that apparently jump starting these can sometimes damage the DME, I have never jump started it but it could have been damaged by the previous owner. As you can see by the pic in the first post, the VVT motor and the sensor are both causing errors. Both the parts have recently been replaced to fix this problem with no success. I have a feeling its not a short because i imagine that would cause problems with other components, but I may be wrong about this. As far as I am aware the motor and the sensor voltage supply run on separate cables (though they come from the same port on the DME).

Im assuming there is always the open up the dme option but that is probably too much hassle for me as I imagine there will be multiple problems in there if it is. Given they are surface mounted components I will probably just won't even try and by a new DME (and all the other components you need to go with it).

The engine used to be a lot worse but over time I have sort of been eliminating the problems. I did a ISTA / P session recently and upgraded everything and that seemed to fix some of the problems also. It runs, and is only rough on idle, though something just seems off. Its not very responsive, it doesn't like going up hills. And I really don't have any more diagnostic information other than this.

If you read my previous posts you will read about the battery terminal, one of the fuses was actually damaged. This may have actually been damaged which might have been what caused the DME to become faulty. I just don't get any errors from the DME it self and for the most part the car works fine.

TL/DR - Putting all of this in to a question, does any one have any other suggestions of what could be the cause of this of the volatge and target value being off?

I have looked everywhere for information on what causes this but no forum posts seem to answer this conclusively.

[mace0]

Bumping this up as I still haven't been able to find a solution. I did manage to fix the rough idle problem, this was caused by a combination of clogged injectors, and some how a whole heap of oil had managed to be collected in the intake manifold. Im going to assume that the hose that goes to the valve cover was the culprit as it was really clogged with gunk also and I assume after so many KMs it eventually gets some oil in there (I actually have read on a lot of forums people with the same error as me complaining of the same symptoms but nothing about checking the manifold. Because there isn't a sensor there I wouldn't be surprised if this is actually a problem a lot of people have).

Though I still can't find a solution to why my eccentric shaft sensor has these readings. Does any have any ideas? I have replaced the DME and checked the harness for shorts and I'm still getting the same readings as the image in the first post. So thats 12V when it should be reading as 4V-5V, its the same voltage as the battery reads in ISTA /D. Then there is the alignment angle, which I am not sure how both of them came out of alignment. The sensor is new also, I may put this one down to too complicated given I can't see any obvious problems as a result. Im just worried this will cause problems down the line. If anyone has seen either of these readings before, if you could explain what you did to fix this I would really appreciate your input. Thanks.

[Kishanrajer]

Hello , recently the car started to show lack of power and warning on the instrument cluster

2A59 and 2A5B
DME valvetronic essentric shaft sensor

I changed the eccentric shaft sensor and the valvetronic motor but the eroor still pops up , it's a n46

[noelka1119]

#9 you find out what was the problem? Because my car have the same error now.