What causes the auto tranny to shift?

[Sarthos]

My 93 accord with stock automatic tranny no longer shifts automatically, but what causes it to shift? At first I heard that it's the fluid pressure, but I checked the fluid, and that's still good. Speedometer doesn't work either, what could do this?

[Losiracer2]

My 93 accord with stock automatic tranny no longer shifts automatically, but what causes it to shift? At first I heard that it's the fluid pressure, but I checked the fluid, and that's still good. Speedometer doesn't work either, what could do this?

shift solenoids for making the trans shift. Vehicle Speed Sensor, VSS for making the speedometer work.

[bcjammerx]

speed sensor is just used to display speed correct?

sounds like either low pressure or a tcu error. No codes? solenoid issue maybe

[TypeG]

is there any slipping?

the transmission is controlled electronically by the TCU and ECU.

usually when something goes wrong with the TCU or a code sent to the TCU, you get a blinking S light or blinking S light and CEL, or just CEL. later.

[Sarthos]

No slipping, just like it doesn't know to shift. How can I check the TCU? I know how to check the ECU, but not the TCU. Also, which one is the S light? And there is fluid, so there should be pressure, any reason why there might not be pressure when I have fluid in? For the shift solenoids, are they inside the transmission or outside of it? How can they be checked?

[TypeG]

you'll only see the S light if you have a Sports Button. that only came on a certain year.

so no CEL?

it's probably is the solenoids like you said. they are located on the top of the trans near the starter. they look like two goldish brown cylinders. i've heard of people taking them off and cleaning them. just be aware of the gasket when you remove them.

i can't remember, but i think they throw a code when they go bad. later.

[Sarthos]

Does anybody have any pictures of them? Since I can't see my car at any time I have internet I need to know exactly what to look for ahead of time

[deevergote]

To get a good idea of what you're looking for, check out the parts diagrams on www.hondaautomotiveparts.com. That's also a good place to buy any replacement parts you need.

TypeG has a 91, so he forgets that the 92-93 models don't have an S light (no sport button). If your D4 light is flashing, or stays on when you're not in D4, that is indicative of a TCU error code. You can check the TCU codes in the same way you check the ECU codes, I believe. The codes are in a sticky in this section.

The speedometer not working is very likely the VSS, as said above. It is always possible that the two problems are related. I'm not very knowledgeable as far as the automatic CBs go, as I've never even driven one... Hopefully someone can offer more help.

[Shag Wagon]

is there any slipping?

the transmission is controlled electronically by the TCU and ECU.

usually when something goes wrong with the TCU or a code sent to the TCU, you get a blinking S light or blinking S light and CEL, or just CEL. later.

I didnt think the auto was controlled by the ECU? I am running a tuned ECU with the automatic components removed from it and it still shifts and runs fine.

[Sarthos]

I didn't check the light to see what gear it said it was in. I just know there is no CEL light, so wouldn't that mean that it's not reading an error?

Is the speed sensor run off of the power steering? I don't see how it's possible, but when looking at the power steering diagram here

http://www.hondaautomotiveparts.com/...S.+HOSES-PIPES

I noticed there are numerous pieces which say they have to do with the speed sensor. (like 10 and 12). If one of those were disconnected, would that disable the speed sensor? I don't see how that's possible, since the speed sensor shouldn't need power steering or power steering fluid.

Also, if someone could take a picture of the shift solenoid, that would be really helpful. And isn't the shifting partially controlled by the cable between the transmission and the throttlebody?

[AG17CB7]

Check out this link
http://techauto.awardspace.com/transmission.html

You can check TCU codes the same way you check ECU codes. You can take the shift solenoids off and clean them with carb cleaner. You can clean the gaskets soap and water or buy new ones at Honda which is about $20-25. They're bolted on the transmission by six 10mm bolts since there's two pairs of solenoids. The lock-up control solenoids is the top one, the shift control solenoids is more towards the bottom.

[GearBangnAccord]

Ur questions are misguided and scattered and you've yet to tell us how this has happened cuz im sure it just didnt happen overnite.
just take ur car to a certified technician cause u obviously arent qualified to diagnose ur transmission issue which are quite complex.

But... if u insist i can tell u from the sounds of things and from my experience with AT it is ur shift solenoid each one controls a different gears shift point so corresponding with the gear ur car is stuck in is what solenoid is dead.

As for ur speedo u need a VSS there is a DIY in the forum that may assist u in swapping that out.

[C91BLX7]

Computer controlled.

If you can manualy shift it then its the computer.

If it shits on you can you cant get it to do anything its the trans/solenoids

[Sarthos]

What happened: I recently removed the power steering and did a ROH swap for my front brakes. After it was done (although the car also sat for about 6 weeks before the last time it was used) the car had no speedometer and the car wouldn't shift automatically. Park, Reverse, Neutral, 1, and 2 all work, but if the car is shifted into D3 or D4 it won't automatically shift. I can't remember whether it caused the car to downshift to first or if it stayed in second if I had already shifted to second.

If it's a computer problem, could a lack of a speed reading cause the tranny not to know when to shift?

[GearBangnAccord]

What happened: I recently removed the power steering and did a ROH swap for my front brakes. After it was done (although the car also sat for about 6 weeks before the last time it was used) the car had no speedometer and the car wouldn't shift automatically. Park, Reverse, Neutral, 1, and 2 all work, but if the car is shifted into D3 or D4 it won't automatically shift. I can't remember whether it caused the car to downshift to first or if it stayed in second if I had already shifted to second.

If it's a computer problem, could a lack of a speed reading cause the tranny not to know when to shift?

the solenoid is the culprit i forget which one controls D4 n D3 IIRC its the ones on the front of the tranny below the dizzy across from the front cross member.
Swap em out with Jy ones (grab a few) and see if this solves ur problem