auto code won't reset

[ss2115]

Hi. 1995 850 - normal 2.5l non-turbo automatic started flashing its engine fault orange arrow. No change in the cars behavior. meant to get to it on a w/e but it fixed itself and went away.

Last week it came back. Did the engine and auto code extraction (no OBD - just the A & B boxes behind right-hand headlight) and it gave code 2-4-5 for the auto and the engine is completely clean at 1-1-1.

Looked up and saw "Break or short circuit to earth in torque limiting circuit".
As it isn't immediately clear to me what this was, I tried to clear the code and see if it reoccurred again. However, it won't clear no matter what i do. It doesn't clear and come back - it just won't clear at all.

So my question is twofold:
1) any ideas on why it won't clear. I can understand if it cleared and returned, but it should at least clear shouldn't it?
2) any ideas on what the fault is and where to look. The car doesn't have traction control or anything fancy - its a very basic 850 SE 2.5.

I tried searching this forum but the fault term is too long.

PS: I used port A1 for Auto and port A2 for the Engine codes as per the Haynes manual I have. I saw also that sometimes you have to clear the engine codes before the auto codes would clear. So altyhough I had 1-1-1 on engine, I went through the clearance procedure anyway and then tried the Auto clear again but it made no difference.