DIY: S65 Throttle Actuator

[M3MPH1S]

Actually here's some additional pics that may help.

Once I got the front part of the wiring harness unplugged, I used a bungee cord to keep it pulled back out of the way. Honestly, the first time I had to unplug the harness (for a different repair) it was the worst part of the repair. Many of the plastic plugs were reluctant to come apart. The most helpful tools will be a second pair of hands and 2 sets of regular old pliers so you don't wear your fingers out.

The next tip I can give you is when you take the "arm" that connects the throttle flaps and the actuator off, I found it very easy to stick a flathead screwdriver in between the arm and ball joint and use a twisting motion to simply leverage it off. When putting it back on, I set it in place and then used a pair of pliers to squeeze it over the ball join and it went on without any fuss.

Lastly, if you've never taken the plenum off, it can be a bit tricky the first time - especially getting the rearmost screws loose. One thing that took me a while to realize was that if you put your head down near the front, and shine a light from the back/side, you can see clear through all the way to the back so you can find the bolt easily. Also some of my plenum/ITB clamp bolts were quite grabby and kept wanting to steal my socket, so I found it helpful to use a deep socket (6mm) even though it wasn't necessary just because it made it harder to lose. And keep a long reach flexible magnet nearby just in case. Specifically I used a 1/4" drive ratchet with about a 6" extension and a deep socket and I was able to reach all of the ITB clamp bolts without issue. The front left is a little tight with the power steering reservoir in the way but it can be managed without much difficulty, or you can always use a slightly shorter extension or unbolt the reservoir (but it's not necessary). Oh and for the hose on the very back of the plenum, it's ten times easier with a second person. The hose connection is just a simple collar that needs to be squeezed on 2 sides, but the 2 sides are a a weird/tight angle, so the way you need to position your arm messes with your ability to pull the large plenum off. You can get one of you to pinch the hose and the other can pull the plenum free.


-

[The Father]

So I called around and a place I get discounts thru autocross is going to do the work for $310!!! Woot Woot! I would have paid twice that to save my lower back. Work to be done Friday.

I'm fairly mechanically inclined. Thats not so much my issue as leaning way over that glorious engine for 4 or 5 hours.

Had to drive on highway in rush hour today....not fun. Tops out at 80mph!

Most say theirs goes into limp with heat. Mine is the opposite. Mine goes into limp when cold. When I start in cold morning or if its been sitting a while it will go limp. If I park for like an hour, then get back in, it will take itself out of limp (no clearing codes).

[The Father]

Thumbs up on those pics though!

Man, those are the clearest I've ever seen posted.

Those will help a ton of people.

[mharris2007]

Originally Posted by The Father

So I called around and a place I get discounts thru autocross is going to do the work for $310!!! Woot Woot! I would have paid twice that to save my lower back. Work to be done Friday.

I'm fairly mechanically inclined. Thats not so much my issue as leaning way over that glorious engine for 4 or 5 hours.

Had to drive on highway in rush hour today....not fun. Tops out at 80mph!

Most say theirs goes into limp with heat. Mine is the opposite. Mine goes into limp when cold. When I start in cold morning or if its been sitting a while it will go limp. If I park for like an hour, then get back in, it will take itself out of limp (no clearing codes).

They’re still making $160/hour which is pretty good in my book. I replaced them in 2 hours flat at my home garage. I have experience building air cooled vw engines and doing general car maintnemnce fwiw.

When the ta first goes bad it will only go into limp mode when it’s warm. As it gets worse it will begin to do it when cold as well.

[kikkoman]

Omg why is it sooo difficult to put the damn plenum back on!! I'm done replacing everything and been trying to reinstall but stuck trying to put the plenum back on. I'm not the strongest person but just can't get enough weight on it to pop the damn thing on!. I've loosen all the clamps as much as I can without any moving around too mich but it won't drop in. Any good suggestions or smart tips??

[M3MPH1S]

Originally Posted by kikkoman

Omg why is it sooo difficult to put the damn plenum back on!! I'm done replacing everything and been trying to reinstall but stuck trying to put the plenum back on. I'm not the strongest person but just can't get enough weight on it to pop the damn thing on!. I've loosen all the clamps as much as I can without any moving around too mich but it won't drop in. Any good suggestions or smart tips??

That's odd. The only issue I've had is that I didn't loosen the clamps enough but it only took a handful of more turns to get it loose enough. Are you sure it's not already all the way in? Maybe take a picture of how loose your clamps are?

[Lambro]

Use a bit of silicone lube on your finger and put it on the inside of the rubber sleeve.

[The Father]

It is done!

Changed plugs as well.

I don't notice any difference at all....which I guess is fine.

Both TVAs were originals. So they had 101,XXX on them when swapped. My passenger side was the culprit. My failure appears to be mechanical and not necessarily chip related. It was significantly more difficult to operate the gears.

My plugs looked excellent. I bought the car with about 80 or 85k miles. So me thinks the place I bought from did indeed put plugs in it.

So they had low miles on them, but a few track days and about a dozen autocrosses.

[pbonsalb]

With the install DIY, you can buy the refurbished actuator from Abdul at M Power Motorsports and save some money on labor and not have to worry about trying to fix the actuator yourself.

I tried fixing my own. Spend the money on new gears and the time to change them. Did not work. I must have installed and removed the actuators half a dozen times trying to test and swap them. I spent money and wasted time.

Often the faults are the electronics, although the gears may be worn as well. If you do all the research like I did, you will find reports of people changing the mosfets, which you can do if you want to buy them and are good at desoldering and soldering and don't think you will screw up other circuits on the board, but that did not fix things for most who spent all the time trying. The reports are very mixed. Probably if you are a real electronics guy with the right test equipment you could figure out the faults on the board.

I ended up having to quickly order a new actuator last year and paid about $650 for it. I just got a second refurbished actuator from the place above. Seemed like the best deal to me. After a few discussions with Abdul, I realized he knows what he is doing. Though he could do this service on his own, he is also working with Jason from Rebuild UK who has a business over there refurbishing the actuators. Much cheaper than a new one, and the new one has the same parts that failed in the original one.

[deansbimmer]

Actuators can be found brand new online for 460$. I pay $390 for them. They’ve come down in price a good bit now, they’re no longer a prohibitively expensive item.

[rich22]

Thank you so much for this thread. Changed an actuator at the track today, under 2 hours, and I am good to go.

Rich

[Joe Dirt]

Originally Posted by jcolley

No clearing of codes required. Do you know the exact error codes led you to the correct actuator?


Edit: Re-read posts...The DME conducts a "pre-drive" test when the ignition is turned on before the engine is started. It cycles the actuators fully open and shut and detects any errors in position. So, the error code may be stored, but will not actuate limp mode if the test passes.

Ok so I have intake off and both arms just kinda rattle... they do not open.
Both must be bad?

[Joe Dirt]

Originally Posted by Joe Dirt

Ok so I have intake off and both arms just kinda rattle... they do not open.
Both must be bad?

Ran carly got #6 misfire. Swapped with a new $140 coil and all seems good. Still have increased emissions. My coils all have 80k on them so coils and plugs here I come..
Where is the cheapest place.to get new coils?

[Joe Dirt]

Originally Posted by Joe Dirt

Ran carly got #6 misfire. Swapped with a new $140 coil and all seems good. Still have increased emissions. My coils all have 80k on them so coils and plugs here I come..
Where is the cheapest place.to get new coils?

Anyone know what code P0020 is? I dont have access to carly till tomorrow

[DV003M]

Originally Posted by Joe Dirt

Anyone know what code P0020 is? I dont have access to carly till tomorrow

I believe it is a camshaft position actuator fault code.

[NJK324]

Thanks for the DIY, just did this on mine!

Does anyone know what the tightening torque specs are for the 6 actuator bolts? Cant find it anywhere

[M3MPH1S]

Originally Posted by NJK324

Thanks for the DIY, just did this on mine!

Does anyone know what the tightening torque specs are for the 6 actuator bolts? Cant find it anywhere

They are not very tight, just snug should be fine. Even the BMW TIS service manual does not list a torque.


https://www.newtis.info/tisv2/a/en/e...l-unit/Hk4mWh9

[Gloggman]

Hi Folks,
New to forum, looks like a nice group.

Did a DIY throttle actuator rebuild incl. gears and replaced MOSFET which was burnt looking. When opening the bank 2 actuator there was the distinct smell of burnt electronics....
Replacing MOSFET was pretty easy (see other posts). As a note to DIY people: don't forget to put conformal coating back on mostfet after replacing it. It helps protect circuit from dust and moisture. Make sure you get the "high heat" kind. I got the MG Chemical p/n 422-55ML from Digikey ~$25...

At the end of the day it did not fix the throttle actuator problem. Worked ok until I accelerated a bit harder now back in limp mode again. Haven't pulled actuator apart yet, but noticed when idling bank 2 TA is wide open. When I turn car off TA goes back to closed position.
Could it be a problem with Throttle position sensor, fooling the actuator to think it needs to stay open and eventually burning up the mosfet?

If MOSFET keeps blowing (seem to be mostly on bank 2 according to posts) there must be a reason. Some posts recommend lube on linkages (makes sense).
But what about the throttle position sensor?
Any thoughts on this?

Just didnt wanna drop $600 on a new TA yet...

Cheers,

[Gloggman]

Quick update on this TA project.
Suspected throttle position sensor problem and took it off. Cleaned contacts,
reassembled and noticed TPS shaft had no "key" feature and could be turned 180deg. Figured engine does not care how shaft is positioned, 0 or 180 deg probably knows by start pre-check routine somehow.

So something got fixed messing with TPS because now TA is working fine and does not stay open during idle anymore on bank 2.
Engine still in malfunction mode with DSC, DBC malfunction on dash etc. but idles perfect but with max rpm of ~ 3000

Invested $65 in Carly app and $20 ODB2 BAFX scanner. Very cool!
Previous 2B28 and 2B5C code cleared. But now I'm reading CDC0 fault code. Says "Throttle CAN bank 2"
(also throws 2B57 "engine emergency program" which makes sense).
Tried resetting codes but no luck. It's probably very valid.

Would TPS problem throw CDC0 code or is it the TA?
(Big difference $45 or $600 part cost)

If anyone has seen CDCO code your comments would be very much appreciated..!

Thx!

PS; Battery went low trying to fix this and had to put it on charger.
Some repair shop said I may have to recalibrate steering angle sensor etc.
I think that probably not issue....

[Majdi]

Originally Posted by Gloggman

Quick update on this TA project.
Suspected throttle position sensor problem and took it off. Cleaned contacts,
reassembled and noticed TPS shaft had no "key" feature and could be turned 180deg. Figured engine does not care how shaft is positioned, 0 or 180 deg probably knows by start pre-check routine somehow.

So something got fixed messing with TPS because now TA is working fine and does not stay open during idle anymore on bank 2.
Engine still in malfunction mode with DSC, DBC malfunction on dash etc. but idles perfect but with max rpm of ~ 3000

Invested $65 in Carly app and $20 ODB2 BAFX scanner. Very cool!
Previous 2B28 and 2B5C code cleared. But now I'm reading CDC0 fault code. Says "Throttle CAN bank 2"
(also throws 2B57 "engine emergency program" which makes sense).
Tried resetting codes but no luck. It's probably very valid.

Would TPS problem throw CDC0 code or is it the TA?
(Big difference $45 or $600 part cost)

If anyone has seen CDCO code your comments would be very much appreciated..!

Thx!

PS; Battery went low trying to fix this and had to put it on charger.
Some repair shop said I may have to recalibrate steering angle sensor etc.
I think that probably not issue....

Faulty TPS doesn't usually put the car in Limp Mode. Pretty confident it's your throttle actuators that have failed.

I was in the same position as you few months ago. Car went into Limp Mode. Open the actuators up myself. Replaced the gears, and the MOSFETS. Worked temporarily. But then went in Limp Mode again. I ended up just buying Remanufactured units from M Power Motorsports. Well worth the $350.00 per unit and all these time I ended up saving.

I was told that my actuators Motors had failed!

[deansbimmer]

A faulty TPS can certainly put the car in limp mode. If the DME doesn't know the position of the throttle, it can't calculate fueling or anything else that requires position input.

It does sound like an actuator issue, but if you removed and cleaned the TPS you need to perform the throttle valve actuator test in ISTA-D. It's a hall sensor and all adaptations need to be relearned.

[Gloggman]

Thanks for the replies.
I agree a bad TPS would probably cause all sort of fuel mixture problems.

I should just get a new one. Probably well spent $40 to eliminate TPS being bad.
I'll probably end up getting a new TA unit also. After looking at many posts on this issue problem seems to reoccur fairly soon after replacing gears and MOSFETs etc. If it's a track car no big deal, but if you get stuck in limp mode 500 miles away from home $1200 is worth it and piece of mind.
At least better than +$3000 from stealership.
I'll send an update asap.

This is a well known by bmw (and expensive to fix!) problems is really something they should be held accountable for. Even if out of warranty...


Good news is finding this cool forum and getting familiar with scanner tool...