E90 M3 Throttle Actuator? - Error codes

[nmcgowan 2]

Hi,

A couple of weeks ago my M3 went into limp mode as I started it - Tyre pressure sensor, Traction control and Check Engine lights. I got the car home and the next day I started it and the lights were gone and car was fine. The issue reoccurred about a week later so I bought a scan tool to pull the codes and started researching. I have some ideas what I'm chasing but Im after others opinions as the fix doesn't sound cheap so I want to make sure I do the right thing. For good measure I pulled the codes again tonight.

First time about 2 weeks ago: CDC0, 2B21, 2B2D, 2B22, 2B15

Second time a week ago: CDC0, 2B57, 2B21, 2B25

Tonight: CDC0, 2B57, 2B15, 2B2D

I was told "Most likely the actuator on bank 2" by BMW when I took it in but Im not happy with their very vague diagnosis nor their quote.

From what I've researched it sounds as if one banks actuator could have worn gears (bank 2) and the other could be electrically failing (bank 1).

My plan is to remove the intake, lubricate the throttle linkages as BMW said Bank 2 was stiff, swap the electrical covers only between the actuators and then see if any of the codes swap banks. Hopefully that might tell me if it is an electrical or mechanical issue.

I've also read that it could potentially be the common issue of the worn gears inside the actuators - in which case Im more than happy to look at purchasing a custom heavier duty gear set from the UK - at a fraction of the cost of a full actuator. Only thing is... I want to be certain this would fix my issue - not buy a gear set to then fit it and find my problem was electrical all along.

What are others opinions on what the codes mean, my approach to get some diagnostic certainty and my options to resolve. If my only option is to buy 1 or 2 actuators then so be it...but I want to be certain.

Edited April 28, 2015 by nmcgowan

[nmcgowan 2]

I've done a LOT of research subsequently and ended up just biting the bullet and pulling the actuators in my M3 out myself to see what was going on with them. Sure enough... the gears were all pretty badly worn. A very well known BMW dealership in AKL told me the only options were to replace the full actuators, fully re-program the entire electronics on the car (???) and that it was best to replace both at the same time. They quoted me $1750 +GST per actuator at two weeks ex-Germany to get the parts. I did a lot of searching and worked out I can import brand new OEM actuators straight off the internet and paying customs, freight, GST and currency conversion for about $1000 each. The dealer also quoted me 8-10 hours labour to replace them. Having just pulled them out myself it probably took me about 2 hours tops to remove them using guides on other forums - it will probably take me even less to re-install them. So they can go jump with their quote for 10 hours!

One crazy thing to note.... all brand new actuators still have the exact same issue with the gears wearing as they contain identical parts as the very first actuators used. - Siemens VDO, who make them still use the plastic on plastic gears and same materials. So brand spanking new actuators eventually wear out too so the root cause has never been resolved by BMW/Siemens VDO.

After much deliberation I've decided Im going to buy a pair of aftermarket gear seats from a member at M3Cutters - these are custom machined gears that remove the plastic on plastic contact by using a combination of brass and a different formula of plastic. Theyre about 200 pounds per set so not cheap but should hopefully actually solve the inherent design fault with the OEM gears. If I install them and the electrics fail on the actuators shortly afterwards, as can also happen, then I'll import one or two brand new actuators from the US and then swap my gears over into the new ones.

Heres some really useful links if anyone is interested.

http://forums.m3cutt...ead.php?t=94742

http://www.m5board.c...e-actuator.html

http://forums.m3cutt...hlight=actuator