S Light comes on and off!!

[rollin17s]

Hello all, I have 1991 Honda Accord LX, the S light on my dash comes on and stays on for a while, the car seems to be under alot of stress while the light is on. It will not shift gears and is just plain sluggish. After about 15 minutes the light will turn off and stay off, and the car runs fine. I saw a few posts on here about the same type of problem, but all the others the speedometer did not work while the light is on, on my car the speedometer works the car is just really sluggish.. any help would be greatly appreciated.

[Igovert500]

It was in teh FAQ:

TCU/TCM (tranny control module/unit): Similar symptoms as the VSS, yet this may cause shifting problems, you may lose 4th gear, and you wont have issues with cruise control/speedo/or tachometer. If you do a search for TCU or TCM, you can find quite a bit of info, but basically it is a little electronic box under the kickboard of the passenger seat (where the passenger's feet would be up near the dash) You pull back the carpet, and behind that metal shield there are 2 computer boxes...I forget which is the TCU (I want to say the one on the right, but double check that before you take my word on it). Anyway, the dealership will charge huge amounts of money for a new one. So go to your local junkyard or ask around on here. Typically you can find a used one for $50 or less. It takes 15 minutes for the average person to swap.

[rollin17s]

Thanks IGovert500, would that cause a clicking under the shifter, the car is a automatic. When the light flashes there is clicking under the shifter..It does when it is sitting still..

[Igovert500]

Sorry, couldn't tell ya. Mine never failed, I can only repeat what I've heard. I did remove mine and sell it to somebody though, and I can tell you that is a quick and easy job.

try local junkyards, this board, and possibly even http://car-part.com/
And you shoudl be able to find one for under $50.

[nitebeest]

Maybe the S stands for "sluggish". Or "stressed". Or "shiftless". Or "Snap... time to replace the TCM". I think that if the tranny couldn't shift to fourth it would prob click a bit. Like it wants to shift but it can't.

[Igovert500]

it stands for 'sport', when you click the button on the shifter, the light comes on, and will prolong the shifts, until you are a few hundred rpms closer to redline. I honestly noticed not much of a difference between it being on and off, at the track, but whatever. That's what it's for. When it's blinking, or your D4 light is blinking, it indicates either a tranny issue, or a speed sensor issue. In this case, I'm betting TCU.