1990, 1991, 1992, 1993 Honda Accord transmission control unit fix, park and d4 staying lit 

A suggestion for all the people who has a shifting problems with these cars (CB7 generation with automatic transmission) is to no matter what your problem is get the TCU out and open it. Pull out the PBC board (printed circuit board) and inspect it as well as you can. Start from there when having weird problems with your transmission. Because of the nature of these problems all transmission behave completely different giving you different symptoms. My old Accord 92 was giving me problems with not shifting at all after 15 minutes of driving it, but if I was turning the car off and then restarting it it was fine again (I tought the transmission filter was clogged and needed to be rebuilt but no). It never gave those weird lights on the transmission lights on the dashboard. Some capacitors and two transistors were burnt and my board was beyond repair. A new TCU made my car feel like new again.

Excellent and informative video. As someone else mentioned, there is no need to remove the three plug-ins on the left side that connects to the ECU, just the two plug-ins to the TCU, then remove the main mounting securing nuts and carefully withdraw the entire unit far enough to rotate it which provides access to the three mounting screws for the TCU. Once that is in hand you can easily repair or replace.

i got a 1990 with this issue to tackle. thanks for the info!

Thanks buddy for this DIY video. Now I can fix my friend's AT ECU (y)

Been using the tcu from a 91lx wagon with sport mode on my ex without sport mode. Shifts gears exactly the same and better than my old tcu. Got it for free so i thought why not. Only downfall is that its caused my d4 light to not be on like its thinking my car has a sport mode. What are your thoughts?

Thanks for the tutorial!

I changed all the capacitor and it works fine for me

Just got a 93. D4 on. Shift LS from 1st to 3rd and that it. Thanks!

Can somebody help me I have a 1991 Honda Accord manual when the car is cold it goes when it starts getting warm it Won’t shift in gears

Before I disconnected the tcm, I tapped on the case and the d4 light disappeared and transmission shifting fine. What should I look for to have permanent fix?

Update! This ended up not working...don't waste your time doing this, go get another Transmisson Contril Unit (TCU) from the junkyard or buy a new one. If you don't have Sport shift the model numbers don't matter, trust me

The two smaller brown resistors, where can I get them from and what size are they!? Thanks

this issue is the same for all accord 1990? because i know they came faulty the trans allways fuck up. my accord have been in my parking for about 2 years i can spend money on his transmission :/

Do you know if the Automatic Transmission Control Unit needs to be programmed or is it plug and play?

I have a 93 accord with this issue. At home I’ve got a spare 91 accord auto TCM (with sport button) My 93 does not have the sport button. Will my 91 work on my 93. Both f22 auto sedans

they can be repaired but most people lack the proper tools and skillset to desolder and replace the bad components without damaging the board its also a safety critical device ,, you would have to go through a PCB repair course and invest in the proper soldering tools or have hire a electronic technician with those skills to repace the defective electrolytic capacitors and bad resistors ,, otherwise replacing the TCU is your only option

My 1993 accord shift hard 2nd and 3rd gear it runs perfectly fine in the freeway, already fix transmission unit, before won’t shift to 2nd gear now shifts but hard, any advice

Solution pls :- My Honda bulldog 1999 D4 light always start to blink when the gear change to 3 or 4, but if i off the engine and start again it will stop but when it change to gear 3 the D4 light we start to blink again but my speedometer is not work, i need your advice on how to solve the issue.

does have to be the same part # on tcu will it work..my car a 92 but I got a 93 TCU will it work? thanks

my cars having this problem right now. ok whn i turn my key on the d4 light is on plus the park light. ok so whn i manual shift my car i cn on shift to second gear whn i shift to 3rd an 4th dnt change out

Thank you for you inf,can you please post the link to get the kit for my 91 wagon, my ecu is a A12

Im pulling my hair out did i miss it or did you not say how to find the bad capacitors if you dont see burn out?

necesito tramision 92 motor 2.2 stand

After you remove the first two connectors you can then take out the six bolts on the back before you try to remove the 3 connectors on the left. It's easier to get a screwdriver in to release the locks and pry them out that way.

have a 1992 honda accord coup nt the wagon

The numbers tell if the TCU was manufactured in Japan or the USA. ALWAYS try to get the TCU manufactured in Japan. Those manufactured in the USA are JUNK. I have replaced these a number of times in Honda Accords for people and most times I simply go for 90, 91, 92 models as they are interchangable. I look for Japanese rather than worrying about the specifics of the car.

Could it be the transmission

Everyone: Jonathan H is correct!! I replaced the original TCU in my '93 Accord LX (10th Anniversary Edition) in December of 2015; the original TCU's p/n is 28100-PX0-722 (3LX). I replaced it with a salvaged TCU, p/n 28100-PX0-823-M1 (3LX). I have no idea what year Accord the salvaged one was from, but when I removed the covers from both, the circuit boards matched EXACTLY. The ONLY exception, as far as I can tell, is if it a model with SportShift™, you have to be mindful of matching the part numbers exactly; otherwise, from 1990-1993, you should be okay. **UPDATE** the one I installed in Dec. 2015 finally went out; replaced in Feb. 2018 with salvaged item 28100-PX4-721. I am going to try & replace the burned out capacitors & resistors on the PX0-823 so that I will have a working spare TCU.

Did this, didn't work.

I have a 91 Honda Accord ex coupe with sport mode. It is stuck in sport more or something. Wont shift to 4th gear. Can I replace the TCU with any ?