Can anyone help me?

I have a 1991 Honda Accord. There is a green "S" light on the dash
to indicate overdrive which is activated from the shifter. This green
"S" light (S for sport) is flashing repeatedly once you put the car
in gear. In addition, the speedometer, odometer, and trip meter all
stopped working and the "Check Engine" light comes on after 5
minutes and does not go off. Once you shut the car off and restart it
everything is fine for a couple of minutes and then the process
restarts again. I tried disconnecting the negative batery cable to
clear the codes but the problem keeps returning. My QUESTION is:
will a broken speedometer and odometer cause the check engine light to
go on in this car. It would seem VERY coincidental that all 3 of
these problems would happen at the same time. Also would the
malfunctioning speedometer cause the overdrive light to flash
incessintly. Thanks for any help that anyone can provide.

 

It is very possible that a broken speedometer cable might cause the symptoms
you describe. I had a 92 Isuzu Trooper that had a speedometer cable which
intermittently stuck which caused all kinds of other problems when the
speedo wasn't working. Apparently the engine computer makes adjustments
based on vehicle speed and when it wasn't getting a reading it made
incorrect adjustments to the engine management which caused numerous
drivability issues. Since the Check Engine light predominantly reports
emissions control problems it is quite possible that the engine computer
thinks that the emissions levels are out of the range they should be when
going "zero" MPH as your speedometer is reporting. I would suggest fixing
the speedometer and see if the other problems clear up, I suspect they will.
You could also have the Check Engine code read (Auto Zone will do it for
free) and see if the code supports my theory.