Greetings, hehe what I mean is that the light of O/D uses the computer to tell you that there is a fault in the box specifically (nothing related to the engine in most cases), as well as in the Optra Hold's light, as in the Suzuki Steem uses that bulb to tell the user that there is a failure (when it turns on and off continuously). As I review I have a trooper 94, one day it was fixed at 3rd speed and started to assume checktrans (check transmission), I did not get a scan for it, investigating that I could find out that I could remove the codes by light, search and find that the connector for the TCM is apart from the motor (ECU), I made a bridge in the connector of the TCM and I launched that I had a circuit open in solenoid 2-3 disarma and indeed the solenoid was damaged. Before putting together, the switche passed and there was no longer the box of the box (checktrans). I hope I have clarified this type of failure signaling.