Kyoto now

My girlfriend has a 96 Accord LX 4 spd. AUTOMATIC. For some reason the check engine light keeps coming on about every 2-3 days. It keeps throwing the same code, P0740, TCC (Tourque Converter Clutch) circiut malfunction. I know what a torque converter is and what it does, but I don't understand what all this means. Does any one know what's going on? Btw, the ATF is at the proper level. Thanks!

Kyoto now

Looks like I'm the only one with this problem, huh?

preludepowerh22

You need a transmission. I see that code everyday at work Acc/ody transmissions are awful.

sony224422

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by preludepowerh22 &raquo;</TD></TR><TR><TD CLASS="quote">You need a transmission. I see that code everyday at work Acc/ody transmissions are awful.

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uh.. yeah thats why they last longer than any other transmission out there, and why cars get sold for over 2.5k everyday with more than 200k miles on them. Your right, they are awful.

and for the OP, it sounds like a problem with just the torque converter, and its probably something electric. You could take it into a tranny shop have them look at it.. you'll probably need to replace the converter, and your tranny is fine.

Kyoto now

OK, so do I need a new tranny or no? Just to give you guys some history, the car was purchased used with 96K miles on it. It now has about 127K miles on it. When I first changed the transmission fluid it was damn near black and smelt AWFUL!!! Plus, the magnetic tranny drain plug had ALOT of metal shavings on it. I think this car was probably abused and neglected.

sony224422

Im still going to say you don't need a new one, but i could be wrong.

preludepowerh22

Hmmm, right. I work for a Honda dealer. If Honda has no clue about the Acc/Ody trans issues, why did they extend the warranty to 7yrs or 100k on. As a matter of fact a customer has a Ody in the shop right now getting his SECOND warranty tranny.

But, take it to a tranny shop.

sony224422

on the 96 trannys, i've heard of little to no problems. The 6th gen autos suck yeah, but this isn't a 6 gen there now is it?

benfrankyc

Thank you! Here's my situation: I drive a 1997 Honda Accord SE. I had the transmission replaced just under three years ago and about 15,000 miles ago. I haven't had any problems with it until about two weeks ago when the weather turned really cold. Now, the only problem I have is when the car is cold in the morning, it's a little slow engaging into drive, and I hear a slight whine when I drive. But once the engine is to temperature, then it seems fine.

However, I was driving on the freeway a few days ago when I got the P0740 code, and the car was warm by that point. Any thoughts? It sounds like it might make sense to replace the thermostat. Also, how often should I replace the transmission fluid? I thought it was every 30,000 miles, but it sounds like maybe every 15,000 miles is more appropriate.

kevbone

Hey There, If your transmission is a little delayed when shifting into drive the first thing I would check is the fluid level. In case you've never checked it before the first thing you want to do is start the engine and let it idle until it reaches normal operating temperature. After that shut the engine off then immediately check the level. What your looking for is the fluid level to be in the middle of the upper and lower level notches on the dip stick. If it is low its most likely the issue. Make sure to gradually add Honda transmission fluid a little at a time and make sure to not over fill it. Most people say to ONLY use Honda transmission fluid which you can get at the dealership and I would agree with that. But if your on a budget you might want to consider castrol foreign engine transmission fluid which you can find at most auto stores. Its about 4 dollars cheaper and people say it works well.

In regards to the P0740 code there are a few things you can check and I will start with the easiest less expensive methods first.

Check the fluid level check the wire harness where it connects to the upper lock up solenoid. On the v6 model its located on the top of the transmission directly under the coolant hoses. A solenoid looks like to two C cell batteries standing on end.

If neither of those two issues work you can probably move onto testing the lock up solenoid itself. Testing this is rather easy to do and there are a few good video tutorials on youtube for this.

If everything electrical checks out on the solenoid you might consider
changing the transmission fluid 3 times. Dirty fluid can cause the P0740 code.


If this doesn't work try removing the solenoid and cleaning the screens. They can become clogged with clutch material and therefore stop working.

To remove the solenoid and clean the screens remove it by using a swivel attachment and 10mm socket with an extension.

Lastly it could be the transmission computer itself. Tracking one of these down is pretty easy. Either at a junk yard or on ebay.

If these suggestions don't work it could be some internal issue with the torque converter itself maybe caused by wear and alot of mileage. Keep in mind that its not to big of a deal if the code keeps coming back. Most likely your transmission will continue to shift fine and the only noticeable side affect will be a drop in gas mileage. My accord has the same code and since it first appeared ive put 30.000 miles on it with no other indication anything is wrong. The transmission shifts just fine.

Anyway if these don't solve the issue I wouldn't be to concerned with it.
keep me posted and
Good luck,

benfrankyc

Thank you! These are some great suggestions. I have a busy week at work, but I'll see what I can figure out this weekend.

Again, thank you for your help! I was thinking I'd need a new transmission, but it sounds like that hopefully isn't the case. You made my day!

benfrankyc

Thank you again for your help. I'm here to report back. I replaced the thermostat and put in new coolant, since there was a suggestion that it might be a misread of engine temperature. The old thermostat didn't look too bad, but the gasket was pretty corroded. I also changed the transmission fluid with Honda Genuine. It looked dirty but not horrible, and the bolt had quite a few metal shavings on it. I'm not sure what's normal.

When I finished, I cycled through all the gears and then took it for a test drive around the neighborhood. After a little while, the CEL came on, and now the code is P0715, which seems to be related to the main shaft speed sensor.

I've tried to listen very carefully as I drive, and it doesn't sound like it has any mechanical issues. It doesn't seem to attempting to shift when I would think that it should, but it really doesn't sound like the transmission is slipping gears. I do hear a whining noise as the RPMs rise, which sounds a lot like my vehicle speed sensor did before I replaced it last year.

Is the main shaft speed sensor the same as the input shaft speed sensor? I think that's the same code that I had before I had my transmission rebuilt almost three years ago. In looking at other threads, it looks like I should replace the input shaft speed sensor, and if that doesn't work, perhaps it's the PCM.

Thanks for any continued guidance!

MAD_MIKE

On the right side cover there are two sensors, one is for the main shaft, the other is for the counter shaft. TCU or in your case PCM uses these sensors to determine when/how to shift.

If your drain plug was gummed up with slurry the NM/NC sensors are also probably slurry fouled with gunk.

Pull em out, wipe em off, reinsert.

bob441

You do not need a transmission I have been driving a 1997 lx with the same problem for 3 years I just reset the light but mine only comes on occasionally

benfrankyc

Thank you all for your help. Here's the latest. I removed the NM and NC sensors and cleaned them. And yes, they had slurry gunk on them.

I ran into issues getting them back in, though. The NM sensor went back in just fine, but I can't for the life of me figure out how to get the NC sensor to go back in. I don't have much clearance where it's located, and I can't get any leverage to shove it in. In my efforts, I actually broke off the plastic tab where the screw is inserted.

Any thoughts on this issue? Do I need a new sensor, or is there a way to repair/secure the one I have? Any ideas on how to get it to go in the rest of the way? I tried lubricating the o-ring with some transmission fluid, which seemed to help, but it still won't go in all the way.

On a good note, I cleared the codes, and now it's showing P0720, which is related to the output sensor, the one that is still 1/4" from being fully inserted. So, I think we're making progress.

slowcivic2k

P0740 is set when the converter does not lock up correctly, there are a few root causes:

1: Low ATF (not your problem)
2: Blocked TCC solenoid fluid passages (very likely)
3: As a result of the blockage, a damaged converter clutch (very likely)
4: Low oil pump output due to a restricted filter, and converter exhaust material running through the pump (again, very likely, due to wear and tear)

The TCC solenoid rarely fails in most of these vehicles (I have rebuilt quite a few of these). In most cases, excessive clutch wear causes fluid blockages on the screens of the solenoids themselves. Cleaning these can restore operation, but it is only a temporary fix. Depending on the root cause, the TCC will continue to slip, indicating ones of the root causes listed. A shaft speed sensor failure does not produce this code, as those sensors are what triggers the speed difference when the TCC fails to lock up. This means those sensors are fine, even if they are a bit contaminated, some contamination is normal. It is not possible to have a shaft speed sensor code, and a TCC or slip code simultaneously, the TCC depends on correct shaft speed to trigger.

After a tear down, you will most likely find yourself in a complete rebuild situation, replacing the converter, and rebuilding the clutches. This type of service is typically required at around 120,000 miles on most B7XA, B7TA, and B7VA transmissions depending on driving conditions.

benfrankyc

It's been a while, but here's my latest update. Thanks again for all those who have helped with this issue.

To re-cap, I had my transmission rebuilt about 15,000 miles ago. When the weather turned cold, it started hesitate when shifting into drive, and I hear a whining noise, especially while it's cold (the whining noise sounds similar to the whining sound I heard before I replaced my vehicle speed sensor last year, and the whining noise corresponds with my RPMs -> more intense at higher RPMs).

I first got P0740 when I was on the freeway, but I haven't seen it since then. I changed the transmission fluid, replaced the thermostat and changed the coolant (with Honda transmission fluid and coolant). I then got P0715, which I keep getting.

I took off the input and output transmission speed sensors to clean them. I broke the output sensor as I was reinserting it (without much clearance), so I replaced it with a new one. I checked the solenoid (as was recommended back when P0740 was the issue), and the screens are very clean. I didn't test the solenoid, though, but I can.

Today, I tried a new input sensor, and I still get P0715. The code appeared when the engine was warmer, and I was going up a steep hill. As I went up the hill, the transmission didn't attempt to shift as I climbed the hill. It didn't slip; it just didn't even attempt to shift (as far as I can tell). And then P0715 came on again.

Any ideas? From all the ideas I've seen (and thanks again, everyone, for your help), it sounds like it might be:

1. TCC solenoid (although not likely, since I haven't seen P0740 again, and the screens were very clean)
2. Wiring from the sensors to the computer; Is there a way to test those?
3. The powertrain control module (PCM); is there a way to test it?
4. The transmission? But it really doesn't seem like it's a mechanical issue, especially since it was rebuilt 15,000 miles ago.

Thanks again for your help!

MAD_MIKE

Test the wiring by leaving the sensor hooked up, pull the connector at teh PCM off and locating the wire/pins for the sensor. Check for continuity and correct resistance values. If the circuit is open the wiring may be corroded/damaged. Check the harness and pins in the connecots are clean and tight.
If the harness checks out good, verify the pins/connection at the harness to PCM are good, clean and tight.

If it's not shifting and 15 is coming up, then it is most likely a communication problem between sensor and PCM.

benfrankyc

This is very helpful, Mike. Thank you!

I'm not sure how to trace the wires to the PCM or even how to get to the PCM. Any suggestions? As naive as I am, is the PCM accessible under the hood, or do I go from under the dash?

As for testing, does anyone know where I can find what the resistance values should be?

Thanks again for any help. I really appreciate it.

MAD_MIKE

Pull up the carpet on the passenger side toe board. You will see a plate, under the plate will be the PCM.
If you don't have access to a manual, check wire coloring and striping and look for it at the PCM connector.

IIRC the resistance of the NM and NC sensors should be 400-600Ω.