My 93 Honda Accord transmission has an unusual problem.
When I start the car, the D4 indicator on the dash is always on and when I shift it to D4 it only go strait to 3rd gear. It wont shift to 1st, 2nd or 4th gear as I drive it.
The same thing happen when I shift it to D3 or 2. I already tried to replace the TCM( Transmission Control Module). It went good for only two weeks then the problem came back.
Please I need your help, anybody knows this kind stuffs. I'll apreciate your reply.

Thanks in advace-

 

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.
Below is some info on how to check for codes, TCM location, and most IMPORTANTLY, how to check your TCM.
If you need to get a TCM, please click on this link:
https://honda-tech.com/zerothread?id=1080930
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.

]This is the TCM[/B]



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

 

Hey Carlos,

I just replace my TCM to my 93 Accord coz the D4 is always on, but after I replace it the problem came back after a week. When I open both the new and old TCM just like your instruction to see if there's a burnt out resistor. I notice they have the same part burned-out.

Do you have any idea what might causing it to burn?

Thanks for replying to my post

[IMG][/IMG]

 

Was the replacement TCM a used one? If it is, I suspect that it was bad from the beginning. Honda TCMs have a problem with the capacitors leaking after several years, the leaking electrolye is conductive as well as corrosive. This eats out the circuit board as well as causing it to short out. That's what burns the capacitors.
If you need to purchase a rebuilt TCM, please refer to this post:
https://honda-tech.com/zerothread?id=1080930

 

Count how many times the D4 blinks.

It might be your trans solenoid.

Mine is doing the same thing, I counted how many times it blink and it blinked 7 times which is the lower shift solenoid.