91 535iA trouble check engine/codes continue

[Rigmaster]

Hey all,

I mentioned in a previous post about some minor troubles I had after replacing the driveshaft in the wife's 91 535iA. I think that when I dropped the rear tranny mount, the tranny drooped down enough to pull on the shifter cable a little bit- causing the dash indicator and the tranny to get slightly out of synch.

Got that problem fixed by simply adjusting the shifter cable at the tranny end, all WAS good.

Then I gave the car back to my wife and went out of town for work for 4 days. She called me up and said the car was bucking and jumping and the check engine light came on- she said she barely made it home one time- but then it seemed to clear up (check engine light was still on but car ran better).

I borrowed an "Autoland OB 15" scan tool to check codes. What I got was a code 29- "Speed Signal" and a code 54- "Torque Converter Lockup Clutch". So, I wrote down those codes and then cleared them out to see if they would come up again. As I was clearing codes (car was running), the engine died and the reader picked up a new code 7- "Air Flow Meter".

I cleared all codes and restarted the car, but haven't driven it much yet. No new codes, but I feel certain they will come back.

Can anyone help with a real-world explanation of the 2 codes (Speed signal and Torque Conv Lockup Clutch)??? Which speed signal does this refer to? What are the common failure modes for the Torque Conv Lockup clutch code, etc. Any info will be greatly appreciated.






Bret.

[ryan roopnarine]

if it REALLY isn't a new, independent problem
it sounds like the wire harness on the transmission got pulled too hard. i don't own an m30, but anything that causes a trans program (that isn't internal to the tranny) seems to involve the MAF, TPS, ICV, or an air leak code being thrown on my m50. but bmw made a tsb about it on that car, don't really know about your vehicle.

[Jr ///M5]

Bret, the speed signal comes from the pulse generator located at the rear diff just like the E30's. It's common for the E30 to break the wires at the sensor. It's like the magnetic pickup for the crank signal sensor, only it protrudes into the diff. It's located at the rear of the diff and is shown on the ETK for clarity. The computer could be getting erronous signals from the sensor causing all kinds of chaos. I'd try checking the wires for fraying, and maybe pulling it out to clean it off, maybe it's picked up some metallic shavings. I'm thinking it's causing the rest of the codes to appear.

Hope this helps,
Jr

[Rigmaster]

Thanks Jr and Ryan.



I'm thinking like Ryan (!!!) that it's NOT a new problem, but somehow I managed to screw up the wires going to the tranny...........

I'll check and report back tomorrow- hopefully....

Funny thing is, the wife said she didn't even MOVE the car this time before the CE light came on- she started it up in the driveway and the CE light came on before she even put it in gear.

Bret

[Brazilianbimmer]

Did you get any further on this? I am having the same TCC code.