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06-27-2025LAST POST
MarkFT wrote
I was doing a bunch of other maintenance work at the same time, but I would estimate 5-ish hours, including the time required to rebuild the actuators (probably about an hour alone). The work wasn't too hard, and if I had to do it all over again I could probably do it in half the time.

The biggest slow downs were getting some of the connectors apart (some of the electrical connections and also the hose connected to the rear of the intake plenum).

I'd schedule half a day if you're mechanically inclined and want to take your time/be meticulous. I didn't break any connectors and everything went back together without any issues, so I was happy with the time it took.
How'd the rebuild itself go? Did it fix the problem?
EJT86 wrote
Any one else have trouble with the three actuator bolts? I got all the way up to that point last night but they're ridiculously tight. I might have partially stripped a bolt
I didn't have any problems. Mine weren't on super tight.
W/// wrote
I didn't have any problems. Mine weren't on super tight.
Lucky me then
EJT86 wrote  
W/// wrote
I didn't have any problems. Mine weren't on super tight.
Lucky me then
Hey Erik, how did it go? Got her up and running again?
M3an V8 wrote
Hey Erik, how did it go? Got her up and running again?
Ugh well of course things came up last weekend so I couldn't get to it until yesterday...spent the night taking everything apart only to find the bolts are super tight getting the actuator off...I used a T25 bit but I'm going to buy a T30 and try it because I think it was starting to strip
Yeah the bolts are a bit snug, i sprayed a little bit of PB blaster and they came out a lot easier.
Damn this is frustrating. Codes prior to replacement of bank 2 were.

Engine / Motor
Fault: Throttle valve actuator CAN message
Code: CDBF
Fault: check at lower top
Code: 2B57
Fault: CAN bus off throttle
Code: CD93
Fault: Control module self-test ROM
Code: 277B
Fault: Throttle valve actuator control monitor
Code: 2B16
Fault: Throttle Monitor Bank 2
Code: 2B26

Now periodically getting after multiple clears.

Fault: Throttle valve actuator CAN message
Code: CDBF
Fault: check at lower top
Code: 2B57
Fault: CAN bus off throttle
Code: CD93
M3an V8 wrote
Yeah the bolts are a bit snug, i sprayed a little bit of PB blaster and they came out a lot easier.
T27 is the size and I switched to the 3/8 drive got it done now once I figure out how to get the rod disconnected from the actuator ill be done
Never mind got it...getting the old one out is the biggest PITA but "new" one is in now reassembling
Make sure to double check your sensor connectors, had to take plenum off twice coz my coolant temp sensor wasn't plugged in all the way.
I got it all back together and took it for a test drive. Had the same "increased emissions" warning on startup test drive was regular. Checked to see if that nasty downshift rev noise was there and of course it was...downshift, rev match, harsh noise and straight to limp mode. I guess I'll scan it tomorrow and see what codes come up
Were the faults cleared prior to start up?
M3an V8 wrote
Were the faults cleared prior to start up?
I didn't check the codes prior. I had someone hit the throttle after it going into limp mode and saw one actuator wasn't working so figured it needs replacing anyway so may as well start there
Took some screen shots of the fault codes I got after another limp mode episode. The drivers side actuator was replaced

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M3an V8 wrote
#2 and #3 on the first screen shot, I got those when I replaced my actuators due to the connectors for the corresponding sensor not plugged in all the way.
Do you think I should bother? It's still having the same problems. Maybe avoid opening it all up again to tighten connections only to find out something else needs replacing
EJT86 wrote  
M3an V8 wrote
#2 and #3 on the first screen shot, I got those when I replaced my actuators due to the connectors for the corresponding sensor not plugged in all the way.
Do you think I should bother? It's still having the same problems. Maybe avoid opening it all up again to tighten connections only to find out something else needs replacing
Totally up to you. The thermostat sensor (#16 first pic) right below the "V8" of the plenum, on the thermostat housing, you might be able to see it if its pushed in all the way. I believe the throttle sensors are at the end of each throttle body bank (#5 second pic).

Sorry can't comment on your "torque" fault codes.
Attached imageAttached image
M3an V8 wrote
Totally up to you. The thermostat sensor (#16 first pic) right below the "V8" of the plenum, on the thermostat housing, you might be able to see it if its pushed in all the way. I believe the throttle sensors are at the end of each throttle body bank (#5 second pic).

Sorry can't comment on your "torque" fault codes.
That's alright. Ugh I might have to bite the expensive bullet
Thread referenced by EJT86 in 2008 M3 - DSC malfunction 07-26-2015
W///, thanks again, just swapped bank 2 in 2.5 hours, start to finish. Never done any work under the hood of this car except oil changes. Would not have tackled replacement without this DIY. Like others have said, my knuckles and back hurt, but my wallet is happy! Now to start a bet around the shop when bank 1 takes a dive...
So, is the consensus replacing the gears in the throttle actuators actually solves the problem of 'limp mode'? It's the gears and not the electronics? Does anyone have any experience yet with the rebuild of the actuators? Our M3 is starting to show signs of this problem and $800 just for parts is a little hard to take. Any and all comments welcomed.