Auto Transmission Shift Issue

[93Accordian]

So I was trying to search to avoid creating a noob thread, but I didn't succeed. I drove the Accord that I bought this morning around the block on my lunch break. He told me that it felt like a cvt transmission in that it wouldn't shift. I could tell that it was stuck in a higher gear before I left the parking lot. I couldn't tell if it was second or third, but it definitely wasn't first. I got out on the street and floored it and it stayed at 2,000 rpms until about 45mph, then the rpms started climbing. When I turned the corner to head back to work, I manually pulled it down to first and it dropped gears and pulled pretty good. It still seemed like 1 gear wasn't there. I wasn't sure if it went from first to third or second to third. Could it be a solenoid issue? I'm going to do a fluid and filter change this week hopefully. The D4 light stays on constantly no matter what gear you are in. Any help or guidance will be much appreciated.

[deevergote]

That D4 light is indicating a TCU error code (just as your check engine light would indicate an ECU error code.) Read the thread at the top of this section marked "read this first", and you'll find the info necessary to read and interpret that code. If there is no code, then the TCU itself may be bad (don't assume that until you've ruled out other things, though... too many people waste money on a replacement TCU thinking that will fix the problem.)

[HardInThePaint]

Well, without an actual diagnostic done on the tranny then your pretty much shooting in the dark. But like most of us here we try to figure out the shit before we take it to the "professionals". I drive nothing but autos so my first stop would be the TCU. Easy find in the JY and an easy fix but like I said its hard to tell and I'm sure u don't want to go replacing a bunch of shit when u don't have the first clue what is wrong. But I'm stubborn so thats the way I usually do it. Like Deev said, thats not practical but I just like figuring out shit for the most part.

[93Accordian]

Thank you both for the information. Deevergote, I'll see about checking it tonight.

[stretch JDM]

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.

[93Accordian]

One more dumb question. To check the Transmission codes, do I use the same 2 prong plug as I would for the engine codes???

[stretch JDM]

yes . use the same one , my bad man .

[93Accordian]

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.

Ok, thanks. but, your car is clean!!!!

[deevergote]

Well, without an actual diagnostic done on the tranny then your pretty much shooting in the dark. But like most of us here we try to figure out the shit before we take it to the "professionals". I drive nothing but autos so my first stop would be the TCU. Easy find in the JY and an easy fix but like I said its hard to tell and I'm sure u don't want to go replacing a bunch of shit when u don't have the first clue what is wrong. But I'm stubborn so thats the way I usually do it. Like Deev said, thats not practical but I just like figuring out shit for the most part.

If the TCU is giving an error code, the TCU is doing what it is supposed to do. Replacing it will not fix the problem. You'd only be killing the messenger. A bad TCU MIGHT be the problem, but it's stupid to jump straight to that assumption without looking at other (more likely) things first.

no its located beside the ECU plug. there will be 2 ports.

Is there another plug? That's new to me! I've never worked on an auto, though. All the things I know, I know from reading.

[stretch JDM]

i just sent him a message . no , deev . there is only one plug . i'm sorry for the wrong info . i hope i cleared it up for the O.P.http://www.cb7tuner.com/vbb/showthread.php?t=21259 this will help .

[93Accordian]

If it's the same one then I'll just run out there now and try it.

[HardInThePaint]

If the TCU is giving an error code, the TCU is doing what it is supposed to do. Replacing it will not fix the problem. You'd only be killing the messenger. A bad TCU MIGHT be the problem, but it's stupid to jump straight to that assumption without looking at other (more likely) things first.

This is true but a bad ECU also throws a code (solid CEL indicates that). Just because something is wrong with the TCU doesn't neccesarily means it won't throw a code. You're correct tho, running around replacing shit isn't the way to do it. He should definitely narrow it down a bit more if possible.

[deevergote]

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!)

[93Accordian]

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!)

I was just thinking about borrowing a tcu if that turns out to be the issue. I sit by toysruskid at work and he knows of a couple I could borrow and/or probably aquire cheap.

[HardInThePaint]

I was just thinking about borrowing a tcu if that turns out to be the issue. I sit by toysruskid at work and he knows of a couple I could borrow and/or probably aquire cheap.

Yeah if u have access to an extra TCU that is the same the one u got then I would definitely go that route first. That would eliminate that issue without spending any money doing it.