Auto Transmission Shift Issue

[bobbycos]

if the TCU is bad , you can take it out, and open up the case its in and check for a weird electronic smell. this is a easy way to tell if it is fried. maybe this will help you locate your problem.

The TCU will say what the problem is. If no codes flash, then the TCU itself might be bad. If a bunch of codes are present, then the TCU might also be bad (or a bunch of things failed at once... though in this case, I'd probably try the TCU first.) If it's just one error code, or two, then it's likely that the TCU is fine, and doing as it should do in reporting the errors.

Opening the TCU to look for burned resistors is one way to check, without spending money unnecessarily. Finding someone else nearby that can let you borrow their TCU is another option. They're easy enough to swap out, so it'd be a quick way of checking, without spending money on a replacement (and a junkyard TCU could cost you $20-$50, and there's no guarantee it's any better than the one you have now!)

my tcu had the burned electric smell but mine is extremly specific to my 90 coupe

OP what is the year of your car

[deevergote]

Judging by his name, and the fact that the error indicator is the D4 light... I'd venture to guess it's a 93.

[93Accordian]

Judging by his name, and the fact that the error indicator is the D4 light... I'd venture to guess it's a 93.

I was told it was a 93 the other day when I signed up on here, but come to find out, it's a 92. lol. I've been out there 3 times now and cannot find the jumper plug. It's odd.

[leftouch]

Can almost guarantee its a TCU failure, go to the junkyard and pick one, when I still had an automatic in my lx I swapped one from a 93 ex and didn't have any shift issues.

If you pop the covers you and look closely there are two capacitors that fail and end up smoking final shift resistors.

Read up, this will be a big help.
http://techauto.awardspace.com/transmission.html <-- talks about tcu failure

[93Accordian]

I still, for the life of me, can't find the jumper plug. I don't know if it's been tucked up somewhere or what, but it's nowhere to be found.

[93Accordian]

Well, I finally found the jumper plug. It was right in plain sight. Anyways, I grabbed a paper clip and stuck it in the pins and turned the key to on. The transmission light did not flash, but the check engine light flashed 2 long flashes, or a code 20. Electrical Load Detector. I took it about 2 miles west of my house to a little highway with a straight stretch of about 3 miles. I downshifted to 2nd, as there's to difference at the moment between 2nd and 1st. I floored it and ran it to 6k then slid the shifter foward to d3. It shifted once and the rpms dropped to about 3k. I'm assuming that it started out in 2nd as I was going 65mph at 6k when I shifted. When I hit 70mph it was at about 3,500rpms. From my driving, I'd say that it is currently only operating in 2nd and 3rd gears.

[dano28]

With all the competent electronics manufacturers in Japan, Stupid Honda had the TCU made by OKI in Swanee Georgia...Duh.

The replacement Honda TCU industry is apparently run by hispanics who pretend not to understand english when their "refurbished" TCU's go up in flames. If I sound bitter it's because our nice 93 Aerodeck is now a hooptie with only 2nd, 4th, and reverse. Oh yeah...I should just go to a junkyard..very funny, the TCU's are all gone.

[93Accordian]

After reading the automatic transmission FAQS threa, I'm readily convinced that the TCU is burnt like all the pics show. I'm going to pull it out tonight and check.

[stretch JDM]

good luck man , i was kinda thinking it was the TCU . make sure you stay with in your year range. 90-91 .....92-93...

[93Accordian]

good luck man , i was kinda thinking it was the TCU . make sure you stay with in your year range. 90-91 .....92-93...

Thanks man! There was a paragraph in the FAQS that described my issue to a T, so I figure that has to be it. I'm going to pull it and if it's burnt, then I'm going to take it to a buddy to see if he can solder in new parts. If not, I may ship it to Module Master. I've had good luck with them in the past.

[93Accordian]

Sure enough, the resistors are burnt in the tcu where they all burn. Time for a new one.

[dano28]

A new one ?? According to Majestic Honda these are over $700.00. As a retired AT&T equipment engineer, I can tell you that it's worth maybe $50 and poor technology even for the early 90's.

Hope you have better luck than we have had. We just gave up !!

[op355]

A new one ?? According to Majestic Honda these are over $700.00. As a retired AT&T equipment engineer, I can tell you that it's worth maybe $50 and poor technology even for the early 90's.

Hope you have better luck than we have had. We just gave up !!

Just curious "Gave up" means we have to live with burnt ones?

[dano28]

No..sorry

The burnt one is not in the car.. We were lucky enough to get a used TCU on ebay that gave us 2nd, 4th and reverse. The car is driveable but must start in 2nd and manually shift to 4th. (actually the 3rd position also give us 4th) The TCU error light is permanently on, no torque convertor lock-up so gas milage sucks, no kickdown gear for passing. In other words the car is barely useable, can't be used on the highway. The air conditioning works though.

My wife and I are both retired on a fixed income so we really can't afford any more TCU ripoffs.

Again...I hope you have better luck than we have had.

[93Accordian]

No..sorry

The burnt one is not in the car.. We were lucky enough to get a used TCU on ebay that gave us 2nd, 4th and reverse. The car is driveable but must start in 2nd and manually shift to 4th. (actually the 3rd position also give us 4th) The TCU error light is permanently on, no torque convertor lock-up so gas milage sucks, no kickdown gear for passing. In other words the car is barely useable, can't be used on the highway. The air conditioning works though.

My wife and I are both retired on a fixed income so we really can't afford any more TCU ripoffs.

Again...I hope you have better luck than we have had.

Module Master will rebuild the Accord TCU's for $120. I just bought a used one off of this forum, which should be in tomorrow, so we'll see how it works out. If not, I've got a buddy thats an electronics whiz and he'll probably fix it. Mine only has 2nd and 3rd and it drives just fine. I think you're giving up too easy.