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2008 m5 135k bank2 Throttle actuator

4K views 15 replies 7 participants last post by  sunilshivaram 
#1 ·
I was getting the bank2 throttle actuator error code, and changed the plastic gears, they looked worn out.
However, even aftet changing, i am still getting the error and car goes into limp mode.
932883


Next step is to swap the actuators and see of it follows the actuator or stays on bank 2.

Any suggestions? This DIY takes about 4 hours. On the first attempt, it took me 4 months down time.
 
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#2 ·
I was getting the bank2 throttle actuator error code, and changed the plastic gears, they looked worn out.
However, even aftet changing, i am still getting the error and car goes into limp mode. View attachment 932883

Next step is to swap the actuators and see of it follows the actuator or stays on bank 2.

Any suggestions? This DIY takes about 4 hours. On the first attempt, it took me 4 months down time.
4 months???
 
#3 ·
Yeah, i started taking off everything, and was scared to snap off the plastic intake manifold. It just wouldn't come off. I had to sit and read up a lot, and then I got tied up for the next 3 months with multiple overseas trips and couldn't get back to it.
Last week, finally, I used a long pry bar after realizing the plastic intakes are stronger than I imagined, and they came off.
In the meantime, every two weeks, I kept charging the battery when the car wasn't running.
Once i put everything back, car fired up immediately, no issues. But the CAN message for bank 2 still persists.
 
#7 ·
I would just replace the whole component as it's not just gears that may be the issue. There are various electrical components inside that with age & heat, could go bad eventually.

If you want to save some money by rebuilding it, m motorsports in Michigan rebuilds all the components inside and tests them before shipping. I just replaced mime with the rebuilt ones and no issues so far.

Sent from my EVR-L29 using Tapatalk
 
#8 ·

I can order these transistors and change them. When the parts are cold, they work. So , after changing the plastic gears, it has to be the electronics thats going out of spec when the heat increases. Also, i have noticed, its a lot hotter in the front of the engine bay, where bank2 TA sits. Bank1 TA is further down, and the electronics board is facing the cooler part of the vee.

As a DIY (Penny wise, pound foolish category), with other spare cars, I think this is worth the job. Buying a new part will be the last thing i want to do lol. (PS: am electronics engineer, have soldering equipment and not afraid to use it)
 
#9 ·
Just want to chime in here before you throw more money and time on this rebuild. We have seen hundreds of units in the last year alone. Majority of the time, if not all the time, changing the gears and transistors don’t fix the problem. These are very complex units and there is are many internal components that can go wrong with these. I would suggest either going with the Remanufactured set that we offer at a very reasonable price with a lifetime warranty and never worry about it again. Or buy brand new ones for an arm and a leg.


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#11 ·
Update: error was with bank2 actuator.
I swap them, and error follows the actuator to bank1.
SO - its the actuator.

Now, this gets interesting, the broken actuator exhibits the same error even with brand new plastic gears. When i spin the gears, they work smooth and clean. However, when i mount the electronics board onto the actuator, the gears don't rotate freely. They keep getting stuck sometimes. I swapped the electronics boards and the error follows the actuator with the "broken" board.

Without connecting to any power, the actuator spindle doesn't spin freely when the electronics board is mounted. I closely examined both the boards, and nothing is visible. They look clean.

I have ordered a used actuator and want to try another electronics board from a different actuator. The moment the electrical contacts are snapped onto the actuator (without any power supply to it), the gears don't spin freely. :|
 
#13 · (Edited)
The gears spin freely when i take the electronics card off.
When i put the board back on, without connecting to power source, the gears are sluggish and dont spin freely. How do we account for this.

I am an electronics engineer, just not in electronics for a while.

Are the shorted transistors causing a circuit thats loading the motor electrically when its spun with hand?
The good actuator works smooth when its manually spun.
 
#14 ·
Managed to spot a brand new actuator for $250 on ebay.
I have also ordered a used one for $150.
Bank1 plastic gears are changed now, works clean.
Bank2 has issues with electronics card.
This is now just an academic workout to replace electronic board with another used one and test.
933247
 
#15 ·
Ok THIS IS SOLVED NOW.

Bought a used $150 actuator from ebay with worn gears, and the electronics board was good.
Swapped the board with bank2 TA, and installed new plastic gears in both TAs.
Took the car out and works smooth, and doesn't trigger the christmas lights effect in the car with TA failure.
However, now we have a new problem: possibly drive shaft is loose, and vibrating. Car had its clutch re-done 6-7 months back and was never really tested afterwards due to TA issues.
 
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