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2000 e46 330i : Idle Control Valve stuck fault code - but it isn't !

28K views 30 replies 14 participants last post by  BMW325TI  
#1 ·
Hi all,

My 330 has started surging (i.e. intermittent acceleration) under light throttle in all gears and 3 weeks ago threw up the Check Engine, EML and DSC lights.
I have read the fault codes and they are :

Map Controlled Thermostat
Idle Control Valve mechanically stuck
(I know these aren't the BMW codes but they are all that my reader gives).

I thought that sounded fairly straight forward so I got a new ICV. Fitted last weekend and it seems to run a bit smoother but, you guessed it, fault lights and ICV code returns (interestingly its normally when going up a slight hill).

I have a thermostat coming but why is the error code for the ICV coming up ?

Today I spent the afternoon going over various things (pipes between air filter and throttle body, into ICV, the vacuum pipes, cleaned the MAF) etc but could find no obvious splits/cracks.

Any help much appreciated !

:)
 
#4 ·
No, no sensors changed recently. The cam position was done 3 yrs ago. The most recent work (before the ICV) has been to do with the radiator.

The DSC light only comes up when the EML light comes up (I.e. when the ICV fault occurs) and not when the surging happens (which is pretty much all the time under a constant light throttle).
 
#7 ·
thats what i was worried about it sounds like an electronic or software corruption ECU/DME fault...

this is prolly gonna hurt wallet wise but it needs to be hooked up to a BMW specific diagnostics machine to see what the DME is doing i have read that a DME software upgrade sometimes is available...

when does the DSC light illuminate?

if ya lucky the DSC system or other sensors are sending duff data to the DME..
 
#8 ·
It is odd because (for me) it is difficult to relate a DSC type fault with an ICV fault. When the lights come up the car goes into limp mode - does this effect DSC operation ?
Are you thinking that the surging might be DSC instigated ? The light doesn't come up at that point though. I have managed three days of (slightly jerky) driving between clearing the codes and it (DSC & EML, ICV fault code) re-appearing.
 
#9 ·
an iffy DSC control unit can cause alsorts of issues it is a common failure on BMW's and very expensive..

it hard to diagnose on a forum but you need to approach it from the DSC fault forget the rest as the DSC is the main issue at the moment i think it may lead to or cause the rest of the problems..

is the DSC light appearing on the dash with no obvious actual physical traction problems?
 
#10 ·
and very expensive..
eek.

Aside from the already mentioned light throttle issue then there are no obvious traction issues. The DSC light has come up (& gone off) in correct/expected operation in the last few days on wet man-hole covers (don't you just love the british summer!). Otherwise, no the Dsc light does not come on until the fault condition occurs (typically on a small incline under light throttle).
 
#11 ·
i can only suggest a hookup to a proper BMW diags and live data machine with a geeser who knows what hes looking at and go thru the DSC and DME system..

you can buy DSC units also called abs units second hand or get them remanufactured for a fraction of the price worst case scenario..

engine surging can be caused by alsorts its just it should not intefere with the DSC in anyway in normal situation so it having problems DSC wise is a more serious issue to address first..
although its reporting incorrect data from the DME to the DSC which is strange and points back to the DME again..

chicken and the egg scenario..
 
#15 ·
one of your wheel speed sensors is giving duff readings...especially in the wet.
the throttle position sensor is linked in with the DSC and could give the icv code.
try getting a bmw specific scanner on your car to narrow down which wheel sensor is at fault.
in the meantime you could remove and clean each sensor and inspect the related ring gear on each wheel...use a little silicon grease on refitting to keep water ingress to a minimum.
 
#18 ·
I had a similar problem with my E46, but only once... The fault code only came up with a decent scanner (I got someone to plug a BOSCH one in - costs about ÂŁ20k or something stupid)

When it was plugged in, it cam up with a steering angle position sensor. When it was reset and recalibrated it never cam back:thumbsup
 
#19 ·
I'll have a good look at them then, cheers guys. I suppose an easy test will be to disconnect them (one at a time perhaps) and go for a short test run and see if the faults re-occur. Hope they come out easy !

Actually, thinking about it, the front wishbones were replaced by a garage in May and the fault showed up not long after. Wonder if something took a knock ?
 
#24 ·
Sorry to revive such an old thread :(

I'm new to bmw after a long line of jap cars I've taken the plunge and bought a 330ci,

On the drive home from collecting it the engine emission light came on and it developed a misfire :(

I have since changed all six coilpacks and it now runs sweet as a nut!

Nowwwwww it's doing the same as the topic starters I've removed the icv cleaned and replaced it, cleaned the maf but alas it's still the same.

The code it's showing is for idc :confused: and help would be great