r_jojola

Hello,
So after changing my PGMFI relay (and It hasn't died) I was driving home from work yesterday and the check engine light came on about 30 miles into my 50 mile commute. The check engine light came on but nothing changed about how the car runs or shifts. I took it to autozone this morning and had them scan it and it came back with P0700 and P0740 codes. I checked the ATF fluid and it was 1/2 quart low. I added ATF and reset the ECU. Went for a 20 minute drive and it came back on. I've googled the codes and understand they are "Automatic Transaxle System Malfunction" and "A/T Lockup Clutch System Malfunction." The car is a 98 DX Auto and has 127000 miles on it and like I said it shifts through all gears just fine and reverses just fine. Any ideas?????

ezone

P0740: Basically, the computer detected excessive slippage during a time when the torque converter lockup clutch should have been in lockup, and slip was detected for longer than 15 seconds.

Can't tell you why from where I sit, too many possibilities.

r_jojola

Well I dropped the civic off to a local Honda specialist shop and they called back today. They said they pulled the same codes I did, and the shift solenoids are operating within specifications, no fluid was leaking from around the bell housing, and they agreed it shifts great. The only thing they could tell me to do is take it to a transmission specialist because it may be something inside the transmission. Now I have to decide if this is really worth tracking down. I paid $2300 for the car, it shifts great, runs great...do I really want to pay a transmission shop to look at it, or just keep driving it with the check engine light on and wait till it gives out.....thoughts?

ezone

You could pull the trans.....seems like you're gonna be pulling the trans to do just about anything to it. How many times would you like to pull the trans?

I found a bulletin mentioning missing/damaged O ring, and I suppose worn could also be included as a possible cause of fluid pressure loss to the TCC.

If nothing is found there, replace converter and pray....
If that doesn't fix it, trans overhaul or replacement next.

r_jojola

Well, after looking at my options I have decided to have the Honda shop flush the transmission and put new fluid in it and drive it till it stops. Ill get rental car insurance just incase I get stranded. Everywhere ive read online people are saying transmission swap or rebuild. Well if its not broke (or acting like its broke in this situation) don't fix it. Wish me luck!!!!!!

ezone

I'm sure if you know what to look for you can see the TCC slippage problem.

If the car has a tach I usually notice that the RPM does not drop the few ticks between TCC unlocked and locked, it stays a little high (maybe only a hundred RPM or so) and slightly moving the gas pedal shows the TCC is almost never actually in lockup or it is slipping.

r_jojola

Thanks for the information. Side question, my commute is all PA backroads and I stay in 2nd and 3rd gear most of the time and rarely get over 60mph. Will the TCC do its thing if I stay out of 4th gear? Is this a reason I havn't notice the problem? Ill keep a eye for the slippage tomorrow. They reset my ECU and I drove about 10 minutes today and nothing. We will see tomorrow during my hour commute!! Wish me luck!!!!

ezone

A tidbit of info I found said the checked range is betwen 50-60 MPH and it has to be slipping longer than 15 seconds. I assume if you don't linger for too long STEADY within that speed range the computer would ignore the issue.


Keep a code reader on board so you can erase codes on the fly?

r_jojola

Well I drove over 150 miles today and it shifted and ran like a champ. Check engine light is on....but ill drive it till it stops. Decided to put some Lucas Transmission fix in it....didn't notice any difference.

r_jojola

UPDATE: So I decided to tinker with the civic today. I put the Lucas Trans Fix fluid in yesterday during lunch time, and at the time the check engine light was on because I didn't reset it. Well I decided to reset the ecu today and went for a 40 mile drive......AND NO CHECK ENGINE LIGHT! It must be a combination of the new ATF and Lucas Trans Fix fluid.

r_jojola

And another update....check engine light came back on this morning on the way to work. So ill just keep driving it until it stops.

ezone

Keep a code reader plugged in so you might know if/when some NEW code pops up.
Because the warning light is already on, you might never know if some new and different problem pops up.

A plain basic code reader might be cheaper than $20, worth the minor investment just to keep in the car IMO. I"ve thought about sticking one in my GFs Fit just so she can tell me what the heck the code is over the phone if that ever happens.

r_jojola

Thanks for the idea. What's a good source for a cheap code reader? Autozone?

ezone

I dunno.... Google it?

Wankenstein

Amazon: https://www.amazon.com/Reader-Diagno.../dp/B004IV58AY

r_jojola

Well yesterday on the way to work at 130660 miles the check engine light turned off! I put the Lucas Trans fluid in at 127300...maybe it worked its way in to the problem and fixed it???? Driving conditions have changed since I originally posted this. I have changed from 55 minutes of PA backroads to 35 minutes of continuous 65mph freeway driving. Ill see how long the light stays off now.

ezone

If you never stay in the 50-60 range, it might be a long time

r_jojola

Why only the 50-60 range?

ezone

Re-read reply #8 above.

r_jojola

So I decided to test your 50-60 mph for 15 seconds.....and sure thing light came back on. Got on the freeway and held it at 57 mph, waited 15 seconds...light. Now I'm just confused what this is telling me. If I drive between 0-50 and 60-90 mph my transmission is good? Or is it slipping all the way through the mph band? Is there any fix for this other then swapping out the transmission?


Its interesting that Honda chose 50-60mph for the range for the computer to look for this. I guess back in 1998 the speed limit was 55...so everyone would be in that range a lot, but now with 65 as the speed limit I'm only in that range when accelerating to get to 65 mph.

ezone

If your dog in your back yard barks all night and keeps you and your neighbors awake.....you wearing earplugs to bed doesn't get rid of the problem.

mcnoople

The self test feature makes perfect sense in how it works. It is no different than your daughter being pregnant. Taking the test does change the condition it just gives you a clear indication of the condition.

The self test is the same. It only checks at 50-60 but the converter clutch is still going to slip at different speeds. I would suspect they chose 50-60 because it is a common speed and is near the low end of the rpm range of top gear.

r_jojola

Good analogy. haha. Well I guess I'm just back to drive it till is stops then. Because I'm not going to put a transmission in when is shifting and running fine (to me).