90 Accord EX S light stays ON no Blink codes

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New Member
Been chasing this down for a few days now. 1990 Accord EX 4 door w/180K..

"S" Light on Dash stays on and Car will not shift into 4th...Also it is in either SPORTS mode through 1-2 -3rd or is just holding RPM range in Higher range area because of whatever is wrong.

Followed several Posts to get TCU codes both at first turn on of ignition switch and Jumpering service port. TCU red LED just stays on continuous, Jumpered Service Port "S" on dash just stays on continuous...Tried both methods several times all I get is a steady glow...TCU is a 28100-PXO-932 - Cruise Control works Fine. Speedometer Works Fine. Also did the disconnect the battery trick TCU just glows red (after battery reconnect) on LED and "S" just stays on on Dash and cars continues to forget about 4th and of course lock-up. I'm thinking Shift Control Solenoid 1st choice, TCU second choice will be pulling it out soon to look for cooked parts..ANY thoughts???E


Christmas Car
Sports mode on a 90 accord is just disabling the overdrive...
The button should be on the auto stick, right beside the release button on the knob.
Did you try and press the button?


New Member
Yea we did try the button thing a bunch of times...That would be sweet if that's all it is...Failure mode data from Googling and Search forums indicates its more likely the shift solenoid or the TCU. i did not realize using sport shift mode kept car from going into forth gear as a normal operation..???.We have had the car since new in the "family" and really do not use the feature...E