Ok odd one. I get this strange bump when lifting off the throttle once in a while and I mean like I can do it every couple minutes. If I goose the gas a couple times I get "gearbox fault". It really disrupts the smoothness of the car. It's most noticeable when it's holding a gear and I lift off a bit to cruise and it bumps. It doesn't bang violently but it's surely felt.

Odd thing about it is that if I put the car into sport mode it goes away. Second odd thing is that Jag successfully cleared a "KAM voltage too low" code (1633) at my car last oil change and it's back. If the computer can't keep it's memory does that mean it's not learning the shifting right? My obdb II code reader can't clear this code now where it could before. JTIS says the computer is fried but it runs fine, drives odd now. The engine light and this bump did not occur together, the bump started a couple weeks ago. The engine light has been pissing me on and off since May.

Don't just say "dealer" either. We know they'll try to sell me a new gearbox or computer and I'd rather hear from someone who knows or had the same. Impossible right?

 

Cos, did you see my link in the "Lurch" thread in the s-type area? It sounds like the same symptom, but the re-occurring code 1633 may not be related. I think (oh my, here i go!) brutal would tell you to clear the code, then do a hard reset by disconnecting the negative cable, then touch the positive terminal so as to clear all ECM/TCM memory. Then relearn.

 

I don't have a ZF gearbox unfortunately. 2000 S-type. I tried to clear the code but my code reader will not clear the code. Hard reset does not clear the code.