1993 Honda Accord Automatic Transmission Control Unit Circuit Diagram

Discussion in 'Accord' started by RockyDada, Aug 28, 2006.

  1. RockyDada

    RockyDada Guest

    Hi Folks,

    The AT Control Unit on my 1993 Honda Accord has a busted resistor (R41)
    in it. Without any kind of printed circuit diagrams, I am unable to
    determine what kind of resistor it is. Can anyone help with either a
    printed circuit diagram or the resistance value?

    Rocky Dada
    RockyDada, Aug 28, 2006
  2. RockyDada

    jim beam Guest

    sadly not. unless google quickly spits out the data, suggest a visit to
    the junk yard.

    if the resistor color codes are still legible, you can read them and buy
    another resistor the same value. if they're toasted, the junkyard is
    your best bet. regarding wattage, size matters. if the replacement is
    the same size, you should be fine.

    jim beam, Aug 28, 2006
  3. RockyDada

    jim beam Guest

    ha! if i'd scrolled down...

    you'll have to judge the colors for yourself [not sure my monitor is up
    to the task]


    1/2 watt, judging by an unburnt neighbor. modern resistors are smaller
    for the same wattage than older resistors like this. as long as they're
    not too big to fit, use the largest resistors you can for highest wattage.

    one thing not clear from that first link is the % tolerance band color
    scheme - in this case 5% [gold]. read starting from the end opposite
    the % band. also, the value has to make sense based on preferred
    values. all resistors use certain values like

    if your read value is not on that list, you're reading from the wrong end!

    get back if you have any more questions. color pics help a lot.
    jim beam, Aug 28, 2006
  4. RockyDada

    RockyDada Guest

    Thanks a lot for the quick response back. Luckily, I had access to
    another such unit with the same resistor in good condition. It is
    exactly the same as the one to it's left. The resistor is a 15 ohm, 5%
    tolerance, 1/2 watt resistor. I plan on getting it from the local
    Radio Shack store and work on it tonight. Will let you know how it

    Rocky Dada
    RockyDada, Aug 29, 2006

  5. ----------------------------------

    While you're in there, why not replace some to the capacitors? They're
    famous for eventually exploding, and then it's even harder to figure out
    what they were unless you find the right web page. You can spot the bad
    ones (which have been running HOT) because the plastic label has
    regressed, leaving the top of the caps naked.

    What wrecked the resistor in the first place?

    'Curly Q. Links', Aug 29, 2006
  6. RockyDada

    RockyDada Guest

    I don't find any other components to be in bad shape but thanks for the

    Rocky Dada
    RockyDada, Aug 29, 2006
  7. RockyDada

    jim beam Guest

    yes, but only if they show signs of distress. generally, the quality of
    honda componentry is very good, and one of these factors is capacitor
    size. in the past when i've replaced them, i've had difficulty sourcing
    some of the same types honda uses, and if i do find them, the
    replacement has physical size issues.
    good question! i believe that resistor is in the output chain, so i'd
    definitely check for correct operation of whatever it's supposed to be
    jim beam, Aug 30, 2006
  8. RockyDada

    RockyDada Guest

    Well folks, it did not work out even after replacing the resistor. I
    guess I will have to bite the bullet and buy a new (or used) TCU since
    I don't see any other obviously distressed components. If it's an IC,
    I would definitely not know how to diagnose or fix it. Thanks for all
    your help though.

    Rocky Dada
    RockyDada, Aug 30, 2006
  9. RockyDada

    jim beam Guest

    sorry to hear it. to be honest, if a resistor cooks, there's got to be
    a reason - and chips are definitely a candidate. make sure your
    solenoids are working ok before you discard the tcu.
    jim beam, Aug 30, 2006
  10. I got into this late, but that is a big 10-4. That resistor was dissipating
    several watts (I would guess 5-10 watts, judging by the surroundings) and
    that means a short somewhere. A shorted capacitor or power transistor is the
    way to bet.

    Wrecking yards are the solution, for sure. The circuit board has suffered
    more than I like to see, so even finding and replacing the shorted part
    would be a partial solution.

    Finally - not to worry you too much, but it is worth mentioning - the short
    may be external, like the wiring to the transmission. If so, the replacement
    will do the same thing. It may be worthwhile to remove the cover of the
    replacement TCU so you can shut down power as soon as the resistor smokes
    (if it does). Once that is sorted out, replacement of the resistor should
    get you working again.

    Michael Pardee, Aug 30, 2006
Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.