mikeconover

Hello everyone ! First off i just wanted to say this forum has been very helpful in getting me to the point where i am in my diagnosis.

Brief history:
Bought 1993 accord LX $300.00 GREAT shape -
D4 light was blinking and the car seemed to be stuck in high gear. I had to drive it home by manually shifting down the automatic transmission.
Took it to a mechanic who was referred to me from a friend. He diagnosed it as a bad transmission and gave me a price to replace it $800.00. I let him do it.

Drove car home and the D4 started blinking again same EXACT symptoms.
Started researching and that led me here. I believe I have a burned out something or another (capacitor??) on the AT control unit pxo 722
Please let me know what you think. And how would you approach the mechanic if this is and was truly the cause of the problem?

Frank Allen

90to 93 almost always have problems with tcu, i have owened several and had to replace in three cars, i would have somebody retreive the codes first, i bought junk yard tcu,s fo 60 to 75.00, my mechchanic checked my car out and said the transmission was bad in two of the three, i did not beleive and the tcu fixed em, be sure to get correct number. Your mech is going to tell you your transmission was worn out as a way to get out of this mess, i would ask for my money back if he refuses then take approprate action. most gen mechcanics ive seen around here dont understand honda,s very well.
Frank Allen 92 accord

mikeconover

Trying to load the pic of the module...

Frank Allen

sometimes you can open the tcu and see the defective parts, however they are difficult to replace, i have not been able to see anything visual on any of mine, id recomend simply changing it out. just a opinion, ebay has em rebuilt for 140 guaranteed if you choose that route. some say any 90 to 93 will work, i found this not to be that case, that pxo number is important
Frank allen

night

made in georgia right?

those have bad caps in them that leak. which then burns out some resistors (they turn pitch black and split open). i used to rebuild them all the time.
i havent done one in a while, but off the top of my head, if you hold the connector blocks in your left hand (connectors pointed to the left) the bad area is on the bottom left. the biggest cap will have some darkish goo under/around it and you may see it smeared around.
we usually changed all those caps, a 220microfard, a 33, and... 330? i think.

anyway, if you are up to some soldering, they are only a 2 layer board and extremely easy to rebuild.
you should be able to find the caps at a frys or similar. just need to match the farad rating and a voltage rating the same or higher.

mikeconover

Thanks for the info guys. I was just able to get the pics to load so im giving this a "bump" Any ideas on the specific area that you see on the picture? Anyone seen this before?

tech8

Can you take a picture from the top of the board and post it?

tech8

Looks like the capacitor at C32 leaked. I can't see from your current pic. whether any resistors got messed up too.

The capacitor at C32 might be a 330uf 10v.

Here is more info. to the common problem with the TCU for your generation of Accord.

http://techauto.awardspace.com/transmission.html

mikeconover

Thanks for all the replies.

Wonder if anyone has run into this. I put old TCM back in to take it to a honda dealer to get an "offical" diagnosis so i have some leverage to get my money back from the mechanic who misdiagnosed the problem as the transmission and repalced it to no avial for 800.00

So i put the TCM back in and if I start the car and the d4 light is on before i put the car into gear the d4 light will then blink when i put it in drive and ill have to manual shift. OR at that point ill turn the car on and off serveral times until the D4 Light isnt lit up (in park) then when i put it in d4 drive it will shift normally.

Does this help diagnose the problem easier? THANKS again ! !

tech8

It looks like a problem with the capacitor at C32. There is bluish-green stuff there. The lead on the capacitor doesn't even look connected anymore (although the picture focus isn't that clear). Your problems probably had to do with the TCU.

utterback93

Where exactly do I look for the PXO # because I just bought a 93 accord ex and it has these very symptoms?

Frank Allen

sorry it took so long to get back, the EX and SE uses a PXO 332, PXO sould be on the case of the unit, They are notorious for going out, the LX uses a PXO 721 or 722, some say it dont matter, but i found out it does or at least in some cars. i would bet that is the problem. You should also get your money back from the dealer who did the work.you can also fix the one you have if you are good at soldering or they have them in the junk yards and e-bay as well in the 40 to 80.00 range. hope all this helps, i owened three of these cars and had that rouble ith all three. very common. but not hard to fix, often miss diganosed i have a 2000 model now so i have to learn all over again, and the whole thing is different.

Jessaaaaay

Pull out codes first, and on the picture obviously that capacitor isn't on the right spot anymore. I had a TCU problem with my 93 before (3 months ago) I doubt your transmission itself had a problem. In my car, it ran fine but it jerked a lot when it shifts gear going 3rd and 4th. So I thought I had a trans problem. And I had code 14 d4 blink. Researched more about it. Turned out its about the TCU for 90-93 accord . I looked/opened mine and mine was ugly. Some of the pins were smushed and it was just not right. Bought a new one off eBay since I couldn't find a used one at my place ($100) . Put it on. Then d4 and CEL went away. Check your ECU too might as well. TCU and ECU Right by each other.

Jessaaaaay

PXO #s are on the TCU. It's located under the passenger floor mat. Google it. There's a lot there who can explain where is it and what compatibilities. But if you plan to buy a used one off eBay or wherever. Just stick to same numbers just to be safe :D ya know? eBay has everything. Just pick the "top sellers" people.

Spence Gadson

I have a 92 Honda Accord same symptoms park and d4 light on at start it’s stuck in 1 gear 3rd I think because I can’t go faster than 55 mph took to my mechanic was told I had a bad transmission but I’m wondering about the TCU replacement to fix issue because it just happened randomly they want $850 to replace transmission what do you think?

MAD_MIKE

Passenger side kick panel.
Look for a blue two wire connector.
Jumper it with a wire.
Turn ignition switch to II(ON)
Watch for any codes from the CEL and/or D4 or S light.
Record codes.
Report back here for further diagnostics.

Brian_4thGen

All

Regarding the TCU failures on the 4th gen - after two TCUs failed on my '92 Accord, I discovered that water had leaked into the passenger cabin under the carpet, which apparently damaged the TCU.

Fortunately I was able to repair the TCU (15 ohm resistor) and after removing the plastic cowl cover and water divertor just above the fan/heater air intake, I applied a generous amount of water proof sealant around the air intake duct and in the corner seams between the fender and cowl channel.

As of writing this post, it is too early to know if the sealant has eliminated the source of the leak and I'm convinced that unless rectified, it will continue to result in ongoing TCU failures in the future.

Wanted to share my experience in case others have similar problems.

Brian