I have a '92 Accord EX automatic. When I started it up this morning, both the P and D4 lights on the gear indicator were lit up. When I'm in forward gears, the transmission only stays in one gear, which I think is 2nd judging by how it accelerates. Park, reverse, and neutral all work fine. I've tried shifting into lower gears with the shifter, tried doing it while driving, tried going into neutral and back, but it will only go forward in one gear.

The transmission fluid is at the right level. There are no strange noises when I shift or drive the car.

Does anyone have any idea what the problem could be? I'm thinking it might be something electronic, since there are no strange noises, and since the D4 light stays lit up no matter what gear I'm actually in.

I'd really appreciate any advice. I need to get it fixed, but money is kind of tight, and a new transmission is probably out of the question right now. Luckily I only have to drive it around town right now, but going 3000 rpm at 32 mph is kind of...annoying.

 

Help this man out!

 

As many of you are aware, early 90's Accords regularly have transmission shifting problems (eg. S light flashing or on steady, D4 light flashing, trans takes off in 2nd gear). The most common cause of this is a burnt out TCM.
I have been rebuilding these computers for quite some time now and have some in stock ready for shipping, or I can rebuild yours.
For pricing, or more information, please email me at: cmrvi1@yahoo.com

Below is some info on how to check for codes, TCM location, and most IMPORTANTLY, how to check your TCM.


Behind the right hand corner of the dash on the passender's side (just below the glove compartment) you will find 2 connectors taped to the wire harness with blue tape ( unless someone previously removed the tape). One is a three wire connector (data link connector) the other is a two wire connector. By jumping the two wires on this connector, you check for engine and transmission codes.
With the ignition switch off, connect the two wires together. Have a pen and paper handy. Turn the ignition switch on. The S light (or D4 light if your car doesn't have the S light) should start to flash a code. Might be a combination of long and short flashes. A long flash stands for 10, and short flashes are 1. For example, if the light blinks: long-short-short-short, then that is a code 13. When you find out what code it is, post it and I can tell you what is going on. BTW, 90-93 Accords have a bad habit of burning out the trans computers. So sometimes you won't get a code. The light will just stay on steady when you jump the connector.
If the light doesn't blink when you jump the connector, then your TCM (transmission control module) might be bad.
To verify this, remove the TCM ( it's located under the rug on the passenger side bolted to the firewall. You will find two modules bolted to one bracket. The TCM is the smaller of the two, on the right.
To remove it, you'll need to remove the 4 bolts securing the bracket. Then, unplug both computer modules, and gently remove the bracket.
Next, unbolt the TCM from the bracket.
Remove the four screws that hold on the cover.
Look at the board carefully. If it is bad, you will find a burnt out resistor and a leaking capacitor. If this is the case, I can rebuild it for you.
Email at cmrvi1@yahoo.com and I'll give you more details.


This is the TCM



With the connector pointing down, the bad spot will be in the lower right corner



This is what the damaged part looks like up close

 

My guess would be solenoids...check your AT fluid first though .

But tcm isn't a bad thought; I would go with the least expensive route first.

 

cmrvi1,

First, thanks a lot for your detailed explanation. I really appreciate it.

I found the two wires under the glove box in blue tape. I jumpered those wires, turned the ignition to III, and both the D4 and P light both stayed steadily lit. I tried starting the engine too; no change.

So I then embarked on the mission to remove the TCM. Your instructions were excellent, and everything went just as you described it. You can see some pics at http://car.fastmailstyles.fastmail.fm/ .

(Un?)fortunately, the TCM looks fine, as you can see.

So, I put the TCM back in, plugged it back in, and put the bracket back, and put the carpet back.

I then took it out for a quick test drive to make sure everything was working. It started out just like before. But then it started acting differently than before I took out the TCM! It was better! I can now get 1st gear if I shift into [1]. If I'm in D3 or D4, it stays in 2nd gear all the time. But here's the really strange part: Whereas before I could get about 32mph at about 3000rpm, now I can get 45mph at about 2600rpm. It's almost as if before I took the TCM out, I was in some crazy 1.5th gear, and now I'm in full 2nd gear. Or, I suppose that it could be stuck in 3rd gear now, but the way it accelerates, it seems more like 2nd gear. Though I could be wrong.

But now the bad news: Just as I was turning on to the next-to-last street coming home from the test drive, it started making a noise when I accelerate that it never made before. Perhaps a slight grinding sound. All this time that I've been driving it with this transmission problem, before I took out the TCM, it never made any strange noises. It did accelerate a little strangely sometimes, and the engine sounded a little different sometimes, but that's probably just because it wasn't in the best gear. This was definitely a new, and unpleasant, sound.

Tomorrow I'm going to see if a local garage whose owner used to work for Honda can help. I'm hoping that I can somehow fix this without having to drive it 30 miles into Dallas to a Honda dealer.

In the meantime, do you or anyone else have any more suggestions or advice?

Thank you again for your help. I wish I could say that it was a bad TCM that could be swapped out with a good one, but that doesn't seem to be the case.

 

The fact that it started running better after you plugged the TCM back in means that the TCM was apparently locked in the "limp-home" mode. By unplugging it and plugging it back in, you actually did a full reset.
By the symptoms you describe however, I'd have to say that it appears you have more than one problem.
1) Something caused the TCM to go into limp-home mode.
2) You might possibly have bad or clogged shift soleniods.
3) A grinding noise is never a good thing.
At this point, I think it's probably beyond a DIY diagnosis.

 

Well, time for an update. I had the transmission fluid flushed (along with some other maintenance), but it's still acting the same: 1st and 3rd gear, and 1st gear only when I select it manually.

I disconnected the battery for 20 minutes, hoping to reset the TCM, and then test drove it, and it's the same. Do I need to remove the TCM to reset it, or will disconnecting the battery do it?

I guess the only thing left to do now is to drive it to a Honda dealer. Thanks for your help, cmrvi1 and VRDrvr.