Another TA issue. I'm at whit's end!

Hi All,

Thanks in advance for reading and any assistance. My 08 e92 m3 has gone through the TA issue for a while now. Car currently has 116k miles but engine was replaced under warranty (rod issue) at roughly 50-60k.

Below are the steps/things I've done to address the issue:

1. TA issues began a few years back. I read the forums, various options, and ended up replacing the gears on both initially through the DIY option and all was well for a few months.

2. The code popped back up so I pulled the TAs out again and found I cracked one of the gears upon initial installation. I replaced the gear again, reinstalled, and all was well for a few more months.

3. Code popped back up a few months later. I pulled both gears out suspecting one of the gears was cracked, etc. but everything looked fine. I ended up replacing one of the Throttle Position Sensors (based off forums I read) but that didn't help.

Driving experience now:

1. If the car is completely off and I try to directly turn the engine on by holding the clutch and pressing the on button, car will automatically throw fault codes and enter the safe mode (4k rpm cut off, etc.).

2. I can occasionally start the car without the fault codes by pressing the on button twice (car is on but engine is still off). If RPM limiter doesn't drop to 4k rpm, I can then start the vehicle without the TA faults.

3. Regardless of if I'm in safe/fault mode or not, the car will stutter upon acceleration from low rpm or if I floor the vehicle. Likely misfire issues/code thrown. Not 100% sure but I believe this started after I replaced the throttle position sensor.

As of right now, I have the following codes pending:
PO303 - Cylinder 3 Misfire Detected
U011E
P2100 - Throttle Actuator Control Motor Circuit/Open

Following codes stored in the system:
P0301 Cylinder 1 Misfire Detected
P0300 Random/Multiple Cylinder Misfire Detected
P0303 Cylinder 3 Misfire Detected.
P161F - Throttle Valve Actuator 2 Position Self-Test Fault

Steps moving forward:
1. My immediate step would be to likely purchasing low mileage, verified working TAs with replaced gears. I'm hoping this takes care of the TA codes but don't believe it'll take care of the misfires.

Any thoughts? I'm hoping it's something simple and easy to resolve.

Thank you in advance for any help

My suggestion is: Pony up and get two new TAs from FCP euro who gives you a lifetime guarantee so if/when they go again later, you get your replacement parts for free. Forget used and re manufactured items, or you will be here again soon. Replace the gears or dont on the new one since you would have a lifetime warranty.

My understanding (based on comments from the professional rebuilders) is the failures are not all gears (although that is a large piece), but also some circuitry internal to the TAs.

I had gears replaced in both TAs, errors came back the next day, had both replaced with new units and have been fine for six months.

Got it, I'll start with the replacement then.

What would you guys suggest for the misfire issues? This didn't pop up after the first few TA failures. Really kills the m3 if you can't open up the throttle without the vehicle stuttering/jarring everywhere.

Misfires are typically spark plugs or coils. Your 08 is due for coils if they have not been replaced. They are known to not always throw codes when they are failing, but you are so a good sign to go forward with a full set. Another user had issues with the OEM ones recently, so perhaps go with the BMW branded set even through they are more money.

Mvy wrote

Misfires are typically spark plugs or coils. Your 08 is due for coils if they have not been replaced. They are known to not always throw codes when they are failing, but you are so a good sign to go forward with a full set. Another user had issues with the OEM ones recently, so perhaps go with the BMW branded set even through they are more money.

What he said.

Great. Just to confirm, do you guys think a bad TPS can throw the misfire code? Based off my faulty memory, I think the misfire began happening after I replaced the TPS (not 100% sure).

Also, I looked at the following page for code P2100:

https://www.m3post.com/forums/showpost.php?p=15733134&postcount=74

Code is for Bank 1 (which coincidentally is where cylinder 1 and 3 are). Per the site, one of the ways to fix is:

Replace DKG1 or EDR for Bank 1

Can someone explain what those are? I tried googling but nothing pops up.

aardchua wrote

Also, I looked at the following page for code P2100:

https://www.m3post.com/forums/showpost.php?p=15733134&postcount=74

Code is for Bank 1 (which coincidentally is where cylinder 1 and 3 are). Per the site, one of the ways to fix is:

Replace DKG1 or EDR for Bank 1

Can someone explain what those are? I tried googling but nothing pops up.

Throttle is usually called EDK, DKG is dual clutch trans, EDR electronic data recorder? I’m a bmw tech and I’ve never heard EDR used. Neither make any sense in this context. Sometimes acronyms can have different meanings. I would think throttle but a real bmw fault code would be most helpful

nightkrawler wrote

Throttle is usually called EDK, DKG is dual clutch trans, EDR electronic data recorder? I’m a bmw tech and I’ve never heard EDR used. Neither make any sense in this context. Sometimes acronyms can have different meanings. I would think throttle but a real bmw fault code would be most helpful

I am fairly certain DKG1 is a throttle valve sensor/position sensor and EDR is the electronic throttle valve control, based on just googling "DKG1" and getting the following:

http://wiki.rcollins.org/core/index.php/MSS60_Error:_2B15,_P0638,_P1636,_P2100

Seems to match up with an actuator issue, but actuator failure will throw a ton of codes (mine did), all of which were solved by replacing the actuators.

I don't remember much from my engineering days, but I'm fairly certain the DKG here is an electrical/automotive part that is D-something-KanalGeneratoren, rather than doppelkupplungsgetriebe (double-coupling/clutch transmission)

Changing the gears probably did not fix the problem. The electronics are bad. Buy rebuilt or new actuators.

jd501 wrote

failures are not all gears (although that is a large piece), but also some circuitry internal to the TAs.

I had gears replaced in both TAs, errors came back the next day, had both replaced with new units and have been fine for six months.

The gears get worn, causing the electronics to hunt the play between the teeth, so that causes the electronics to work constantly to maintain throttle position. So the gears get 'rattled' to death and the electronics fry themselves in the process. So when the teeth are shot and you get the error code, the electronics have also had time to cook.

Rebuilding them is a complete waste of time and resources and headaches. Do it once, do it right: get new ones from FCP.

The mpower rebuilds are good. The electronic board is gone through as well.

Thanks all.

Bought a pair of actuators off a member here and TA issue is gone! Can't explain what it feels like to turn on the car and not flinch waiting to see if the TA acts up.

Misfire is way better but I still do feel it so next step will be injectors and coils.

Aaron

Injectors are not common. Do coils and plugs. Start there before touching your fuel system.

Thanks all. Problem I believe has been solved.

Replace plugs and coils (aftermarket non-oem) on 1 and 3. Turned on the car and vehicle went to hell, new codes for coils. I cleaned the oem coils with electric cleaner and swapped and car is running fine now.