nickf109

Hey guys,

So I was driving home from work tonight (2012 c63 coupe) and about 2 min into my drive my traction control kicked off and my engine light popped on. It was driving in safe mode, I guess you can call it. I turned the car off and on again and the traction control turned on and the engine light stayed on. I pulled the code and received the P210B code for
"throttle actuator B control
motor circuit range/performance"
how should go about fixing this, or should I just bring it to Benz for them?

thanks guys!

Celicasaur

Hey Nick, did you ever get this sorted?

I've got the same code and I'm wondering if I should flip a coin to replace either the harness or TB unit.

nickf109

Hey,

So when I took the vehicle to mercedes they just told me outright that the actuator was shot and I had to replace it. The actuator was 1200 with 1800 in labor, I'm not mechanically inclined so I had them replace it.

Celicasaur

God bless you sir - thanks for the quick reply. I wasn't sure if you'd reply, given your post count since when you posted.

I'll try a replacement TB and then report back for future reference.

Thanks man

BLKROKT

FYI I have 2 remanufactured 82mm TBs never used if you want one or both. They came from the Russian guy with his kit, but I got a great deal on new ones. Will sell them for what I got them for, PM me if interested.

Celicasaur

Ahhh thanks for the offer buddy, however I ordered one from an eBay seller a couple of minutes after my last post in this thread

Fingers crossed it solves the mystery on my car.

BLKROKT

No sweat, I haven't had time to post them up for sale so I thought I'd offer. I've been in London this week too so I could have saved you on shipping... I guess if I had known last week lol.

Let us know how it works out

Celicasaur

Whoop whoop, the replacement throttle body solved the issue - thanks Nick


Upon disassembly of my manifold and playing around with the replacement unit and the suspect faulty unit - it was clear to see from the resting position of the butterfly plate. The faulty unit had the small opening/slack that you'd kinda expect to see, but it wouldn't close back any further when pressed by hand. The replacement unit does. This leads me to believe that under the strong engine vacuum, the intended behaviour is to pull back the plate as far back as it will go, ie fully shut for the ECU to then have control over how much the plate opens electronically to regulate the idle etc

In short - my car has gone from idle vacuum of high 14's to low 19's and ignition timing of -7 to -9, to positive 3. Also worth noting for future reference (believe me, silly little snippets of info like this over the last year or so would have helped me so much in my trial and error of so many things) load on a happy engine at idle (M156 of course) should be sub 30 (say, 26-29) and MAF g/s anything from 6-8 i'd say. All of these figures are based on current air temps which are around 15-18 degrees centigrade in the UK.




Interestingly though, I do believe that there is slight improvement to be had by replacing my other 'good' throttle body because that doesn't close as much as the one I just had in...it would explain why my idle vacuum isn't in the low 20's and why my timing isn't close to around 10 degree's. I know that my car used to idle from around 7-10 degree's and I've also seen 23in/Hg vacuum too. BLK - if you can have a play with your throttle units and let me know if they close near enough completely shut when you press your finger on the plates, then I'll buy one of them from you and try it on soon.


Weirdly though, my LTFT is still reading a firm 0 on both banks. I hope that it's just a case of needing to drive the car for a bit to generate some data. My STFTs are in the low teens at idle which isn't great. I haven't driven the car today other than to test the unit...maybe tomorrow.

BLKROKT

Celicasaur

Sorry for the delay man, I hardly come on here as much as I used to nowadays...

I tried many things to figure this out (hell, a replacement harness, countless gaskets, bolts, sealants etc) in the end - it was literally as I explained in the #8 post above. A replacement unit cured it instantly.

Strange that yours has it so soon as it was a new item. Only way to check is to open the belly pan of the intake manifold and see what's good with the plate, ie does it have the capacity to seal shut under vacuum. Apologies in advance if I'm wrong, but that's absolutely what the issue was with my car.

Checking the health with the TBs still in the car - ODB data at idle - if your timing is notably low, or vacuum isn't nice and high, or maf flow is high then it's a hardware issue with the TB(s).

BLKROKT

Celicasaur

I can't remember tbh, it feels like so long ago. I think....it was consistent. After clearing the code, it would always come back for me after a little while. The ODB figures were always consistent though, regardless of the code being there or not.

ODB values...my memory is failing me, but at a guess, you may have an issue with them if:
Timing is in the low single digit figures
Vacuum is in the low/mid teens
MAF G/S is above 15 or so
Intake manifold pressure around 10psi

These are all assuming fairly cool AITs of 50-70F