Re: The D4 light
runderwo
A few years ago I had several transmission problems with my 90 Accord
in this post.
http://www.automotivehelper.com/topic999769.htm
I just realized I never came back and told everyone how I fixed it.
1. The transmission computer (TCM) was suffering from bad
capacitors. I replaced two burned resistors and five electrolytic
capacitors, cleaned all electrolyte from the PCB and repaired a couple
of traces. There is now no "S" light, nor starting off in 2nd.
2. There were bad grounds, at some points there was 12 ohms between
ground points in the car. I sanded and replaced the screws on: the
ECM ground at the thermostat, the valve cover to PS pump to frame
ground, and the 2 ground strap points from the battery cable. There
is now tenths of an ohm between the same points as before.
3. The D4 LED was bad. I got a new one from Honda, pulled the dash
cluster and replaced it. Figures, since it's the LED that is on all
the time. So "being flakey" is actually a failure mode of the LED and
doesn't necessarily indicate computer trouble.
4. The transmission throttle linkage cable was not correctly
installed. This was causing the flaring on upshifts, probably because
the appropriate fluid pressure was not being applied to the clutches
for the high RPM.
So as of now there is no more D4 blinking, no more "S" light, no more
funny behavior, and tight shifts.
Thanks for all your help 3 years ago. I just had a veritable army of
gremlins inside that thing!