Transmission errors that aren't servo gear related

[m5james]

I'm throwing out a wide net here, but I've recently been getting error codes that came up on Google and YouTube searches as a transfer case servo motor. I've dropped the exhaust, wiggled the cross brace out of the way enough to remove the servo motor only to discover that the plastic gear in mine is in perfect condition. At this point I'm at a loss. I've had a random codes and this is a combined list of them from over a year so I'm not leaving anything out on the chance one could cause the other(s):

Engine:
310B
29DF
2ABE

Transmission:
55C3
CF5E - CAN TIMEOUT

Traction/stability control:
6F60
5F2F
D358 - No message (instrument cluster 784)

Instrument cluster:
A3AA
A566

Dynamic management:
D022 - Unknown failure

Parking brake:
D395 - Unknown failure CAN

Car access system (CAS):
A0B8

Parking sensors:
AB0B
AB30

High beam assist:
E0DB - Unknown failure

Infotainment system:
E1E9

Heads-up display:
A4FF - CAN Message failure

All-round vision camera:
CAA4

Gear selector switch:
E094
E095

Traction/stability control:
5DEA

Instrument cluster:
A559 - Power supply switched off
A566

Active roll stabilization:
627A

This list has likely irrelevant items, but I've left them just in case...car access is an error from my aftermarket remote start system and parking sensors is an error from my GF crashing the car and it's missing a front RH sensor which will be solved during my bumper replacement.

I've had ALL the drivetrain fluids replaced at a friends shop who is a former BMW of Seattle tech within a years time, battery replaced a few weeks ago as precaution. Oddly the active roll code has been happening ever since I've lowered the car and I simply can't get it to go away. Lately if I'm driving hard or aggressively, I'll get anything from ABS, DSC and DTC with Brake lights on the dash that'll mostly go away if the engine is power cycled. Worst is I'll get all those lights coupled with what feels like I'm getting kicked in the ass, a gear symbol on the dash cluster and limp mode with zero throttle input that can only be resolved via reading and clearing codes via my Carista app. Tonight I'll be checking codes via my laptop that has ISTA, Rheingold, etc even though I don't know how to fully use these programs.

I'm open to all suggestions and I'll respond or try whatever this point.

[mirob]

Originally Posted by m5james

Worst is I'll get all those lights coupled with what feels like I'm getting kicked in the ass, a gear symbol on the dash cluster and limp mode with zero throttle input that can only be resolved via reading and clearing codes via my Carista app.

I'd hate to be a bearer of bad news but my experience with the symptoms you're describing has been a transmission component failure.

Only difference being, both of these vehicles were pre limp-mode so they kept on going until they didn't anymore.

1994 Taurus SHO (AT) - transmission would slip in first two gears initially. At full stop, had to keep the revs at 1500 to keep torque converter engaged. As time went on (month or so), vehicle would kick hard in every gear randomly throughout the rev range.

Turned out that some gear cogs inside the transmission were worn and it needed a full rebuild. They rebuilt the torque converter as well.

1997 E36 M3 Sedan (AT) - This one behaved more like what you're describing. Random torque converter slip would feel like someone just rear ended me - only happened while driving. It started out as something that one would think is a glitch, maybe once every couple of months...but then it became more frequent - fast. Over a period of six months or so I couldn't drive down the block without it happening.

It was a slipping torque converter. They rebuilt it and it was fine. Eventually the gearbox had to be rebuilt because the insides were destroyed but I don't think it was related. However, the slipping torque converter could have set the wheels in motion for that.

Point of the story, don't wait for this to escalate. I don't want to alarm you but I'd take it to a reputable transmission shop and have them do some diagnostics sooner rather than later. A torque converter is a lot cheaper than a whole transmission.

I hope this is not your issue and you get this sorted out easily. Hope this helps. Good luck man.

[m5james]

I've still got the servo motor apart and I don't like how the motor portion itself feels...its choppy very wobbly within the case. I'm going to look into replacing the whole thing just to be sure. My buddy said there's CANBUS issues so he's determined to think something is getting wet.

Twice it has died while idling...the RPM's dropped, some shaking and then died. I'll hookup my laptop today finally.

[Marek7695]

Hi what was the solution to your problem?
I have exactly the same problem as you describe

[X5MBeast]

Originally Posted by Marek7695

Hi what was the solution to your problem?
I have exactly the same problem as you describe

I think he ended up getting another used transmission.

[m5james]

Yeah, sorry...I ended up replacing the entire trans from a low mileage car for $1400, coded for $150 and it's back on the road. I'm still getting random Christmas tree lights but it's no longer forcing itself into park and is still driveable with all the lights on.

I've logged voltage spikes, which is a common issue on other BMW models. I've already replaced and registered a new AGM battery, so that's not my issue. I looked online and found enough videos to learn that this over/under charging is a Valeo alternator issue so I'm going to replace the brushes in the alternator for $7 vs a $150 regulator or a $800 alternator.