1991 Accord auto transmission - shifts in/out of 'sport' mode by itself

My 1991 Accord LX automatic trans w/237000 mi, recently began shifting in
and out of 'sport' mode by itself. When it shifts into sport mode, the
dash lamp comes on and the transmission shifts to 2nd gear, regardless of
the speed I'm driving. It will not shift back to a higher gear until it
changes back from sport mode...on it's own. If I am stopped when it shifts
into sport mode, the dash lamp comes on and the transmission shifts to 2nd
gear. I have to manually shift to 1st to take off and then shift back up.
As long as the lamp is on, it will not shift beyond 2nd gear. Any help is
appreciated.

 

out of 'sport' mode by itself.

Are you sure that the Sport Mode indicator light is not flashing? That it is
steady? A flashing indicator means that the transmission computer has sensed a
problem.

Just to be sure, check the LED indicator on the transmission computer itself
when you first turn on the ignition. If THAT light is flashing, count the
number of flashes. That tells you where the problem is. On my Prelude and
probably your Accord the computer is under the rug at the passengers feet.
There's usually a little flap of carpet that you can pull back to see the LED.

 

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How many times have you done a drain-n-fill with Honda ATF? I'd do it
once (4 litres), then again after a week of driving. If that doesn't fix
it, the ECU can be repaired, if it's blown a couple of capacitors. I
have a PDF file explaining the fix. I could point you to a link.

'Curly'

 

it needs a tranny computer, they can be fixed but it doesn't always last long.
Chip

 

Where is the transmission computer located??

 

Under the carpet on the front passenger side. I had to buy one at junkyard
for a hundred bucks US, but I changed it in fifteen minutes and no more
problem on my '92 Acc EX. Similar symptoms to yours.

 

Thanks,

I pulled the carpet back and was suprised to see that much equipment under
the rug!! i will start hunting one in the wrecker yards.

Johnemac

 

John -

rug!! i will start hunting one in the wrecker yards.

Now that you've found the computer, determine what, if any, code is flashing at
you when the ignition is turned on. (There's a little window on the smaller
box. The larger box is the engine computer.) You shouldn't replace the
computer if something like a throttle position sensor under the hood has gone
bad. Count the flashes of the LED; that will tell you where the computer thinks
the problem is.