flashing d4 light

I have a 93 accord with automatic trans and when I shift to D4 (which is
like overdrive) the d4 indicator light lights up fine.....after the car
shifts from 1st to 2nd, the light will start flashing and continue to flash
no matter what gear I put it in after that...... now that light will not
light up at all now but the others do (reverse, netrual, etc)....the owners
manual says that when this light starts flashing it indicates there "may" be
a problem with the transmission..........the trans shifts just fine and the
fluid is full and no burnt smell to it, but this has me puzzled.


Also, is there a way to adjust the idle speed? The car when it's in drive or
when coming to a stop wants to almost die out. The rpm's seem way too low.

 

I believe you need to pull the codes from the computer

 

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I can't find the link, but there's some capacitors that get old and fail
in the ECU. Cheap to fix. I'd change the tranny fluid anyhow, but it's
probably the ECU failing at that age.

'Curly'

 

This may have nothing to do with your problem, but a very similar
thing started happening on my 93 Accord. Within a few days, it quit
shifting at all and stuck in 3rd gear. The dealer replaced the
transmission control unit, a VERY expensive part that apparently has
started to go bad in a lot of this vintage Honda. At least the dealer
told me they were starting to see a lot of them. You might check to
see if there is a tech bulletin about this.

By the way, it is my understanding that D4 is not an overdrive, but
there is a torque converter lock-out clutch that engages at cruising
speed in D4 and when it does it feels like overdrive except the car
does not free wheel.

Elliot Richmond
Freelance Science Writer and Editor

 

The D4 light flashes to indicate a fault in the transmission control
electronics. Usually there is a trouble code stored in the transmission
control computer that you can make it blink out.

 

I'm no expert but here are some online manual reference for 1993 Accords as well
as a little of my own recent experience with low RPM:

http://www.honda.co.uk/owner/AccordManual/index.html

For idle speed setting, click on fuel injected or carbureted as appropriate,
then click on "Idle Speed Setting." For troubleshooting, click on the Idle
Control System Troubleshooting guide. E.g. see page 2 of
http://www.honda.co.uk/owner/AccordManual/400/6-192.pdf

Notice that for fuel-injected Accords, for low RPM, the guide suggests the A/T
shift position signal may be the problem and says see page 202:
http://www.honda.co.uk/owner/AccordManual/400/6-202.pdf

Seems like your car's two problems may very well be related.

Another possibility for the low RPM:
My manual transmission 1991 Civic started idling low, to the point it seemed it
might stall out, recently. I had no check engine lights or ECU codes, but, like
the Accord guide above, the guide for my Civic said the problem might very well
be with the EACV (electronic air control valve). I took out the EACV and as I
was doing so found one of the two coolant lines to it empty, like a big air
bubble was in the system. I sprayed carburetor, etc. cleaner into the EACV, let
it dry out (if you don't, the first start-up may be a little rough) and
re-assembled everything, priming the two coolant lines with coolant as best I
could before re-attaching them.

I then did a very thorough purge of the coolant system, per the coolant drain
and fill directions. I'd never left the car idling with the radiator cap off
(per the directions) for 35 minutes before so as to get the coolant fan to come
on two times. This time I did.

My two theories on how I got air into the system: I changed out the thermostat
in March; I'd never done a good purge before when changing the coolant.

Anyway, the result is the car is idling much better. I am not seeing the rapid
drop-off in RPM when I come to stops anymore.

Updates for the edification of all and the group archives are welcome.

Good luck.