Transmisson Problems?

[AngryToddler313]

I just picked up a 93 accord ex auto. the guy I bought it from said it needed a TCU but everything I've read says the d4 light should be blinking but it just stays on. for instance, whatever gear I'm in will light up but the d4 light will always be on. I'm not totally sure what gears I have but I only have 2 of them. the "First" gear hits 30 at about 3000 rpm and the "2nd" gear hits 60 at 3000 rpm, but those are the only two I have. I have to put it into 1 for it to shift into the "first" gear, and if I'm in d3 or d4 it'll shift up to the "2nd" gear but won't shift down to the "first" gear. I'm wondering if maybe its shift position switch or shift cables, possibly a solenoid. I'm trying to avoid buying a whole new TCU because it seems to be the most expensive option, also I'm not sure if there are different TCU's like how there are different ECU's (I believe my car has the pt6 ECU) I appreciate any suggestions or possible causes

[deevergote]

Read this to learn how to pull the error codes, if there are any. If it’s throwing numerous TCU codes, it may be the TCU itself. You can attempt to repair the tcu if you can use a soldering iron and identify bad resistors.

https://www.cb7tuner.com/vbb5/forum/...nd-s-d4-errors

[AngryToddler313]

I tried this and the d4 light stays lit. The parked light is on because I'm in park but the d4 light doesn't blink or flash its a solid light. Same as when I'm driving the car

[Fleetw00d]

I tried this and the d4 light stays lit. The parked light is on because I'm in park but the d4 light doesn't blink or flash its a solid light. Same as when I'm driving the car

That's with the connector jumped? IIRC if it stays on all the time with the connector jumped, then it is a TCU problem. If you're not handy with a soldering iron and finding/fixing issues on the circuit board, there are folks that repair them. I had two repaired by e*ay user mandigital. At the time it was $75 with lifetime warranty. Both worked fine for multiple years until I sold the cars.

[AngryToddler313]

Perfect. I wasnt sure if those ads were trust worthy. Or if there were multiple types of tcu's if I chose to buy a new one. Is there an aftermarket solution for them aka a newer tech replacement or would I have to get a newer aftermarket ecu like a holly and replace both the oem ecu and tcu? Thanks again for the help!

[Fleetw00d]

I don't believe there is a new aftermarket solution for the TCU. Mandigital repairs one you send him. Both of mine he turned around in a day (I had spares to use in the meantime).

[Honda_Lady]

Mine did this numerous times before I lost reverse also and it wouldn't shift into 2nd anymore. So, you have 1st 2nd and reverse? If you don't have reverse, the TCU may not fix it. I replaced my TCU multiple times until I lost reverse also and then it took a trip to the junkyard for the last time.