I have a 91 honda accord lx. The "s" light constantly blinks and the car shifts from 1st to 3rd so I don't have 2nd or 4th unless I put it in manually. The TCU gave me error codes 7 and 15. I removed the TCU and looked at the circuit board and there was corrosion. I ordered a rebuilt one and installed it today but it didn'y fix the problem. My speedometer also occasionally goes down to zero when I'm driving and my radio sometimes will not come on when I start the car. Could it be me ECU? Any suggestions would be great. Thanks!

1. Check all under-hood and under-dash fuses with a test light or multimeter.
2. Clean main VSS/ECM ground on the thermostat housing.
3. If the odometer and trip meter work but speedometer does not, then the problem could reside with the speedometer or the printed circuit board.
4. Check Vehicle Speed Sensor (VSS).

Make sure your transmission fluid has been recently changed. You might also want to look into AutoRxing your transmission, if you think it's not too far gone and that it might have developed varnish or sludge. I recommend synthetic ATF for healthy transmissions. The benefits are numerous.

Hi my honda 1991 is getting in problems when its raining or my car pass where water on the road and it splashed with front tires or environment is humedity then sudenly turn on sensitively highly the "S" on dash board I can used the car without making automatic changes gear for a couples of days but later on when wheter is beter sudenly it come up regular sincronized gear changes, when I run my car under irregular operation conditions rise to example 2800 to 3000 RPM at maybe 45 Mi/hr, when normaly is 2500 rpm and gas gone over fastest, do you think could be some sensor problems like mayve ruber boots damage and where is this located ? Thanks a lot

My brothers accord has the 's' (sport) light that keeps blinking also.. What I did was opened up the tcu(transmisson control unit) and resolder a new capacitor on. The original capacitor burned out and caused the tranny to go into safe mode. This is how I fixed my problem, hope it helps.

Larrley, good job. Leaking capacitors on older Honda TCUs and ECMs are common problems.