P0741 code

[jm69749]

New to the forum, but want to go ahead and thank anybody for any advice. I own a 2005 Vibe, and the check engine light just showed up. Ran the code and it was P0741. I read that after hitting a bump or on a rough road this has knocked the trans solenoid plug loose to cause the code to show up. Not exactly sure if this is the issue, but could someone point me in the right direction as to where this plug is located. I looked at all the ones from the top and all seemed to be tight, but haven't had time to crawl under it. Thanks for any advice!

[JohnO]

I looked at the service manual and there is a single electrical connector for all the solenoids. It it located near the shift cable. Here is some info on P0741:

http://engine-codes.com/p0741_toyota.html" onclick="window.open(this.href);return false;

[TerribleTim]

Just had this code come up last nite and researched it. Reset it but according to the service manual, it takes two strikes / malfunctions to trigger the CEL, so I haven't seen it back yet. This is only the second time this car threw any code. The first time was 11 mos ago and I was on a road trip with no tools and the code reset itself on the next cycle before I found out what it was. I strongly suspect it was the same code and cause. Both times the car was being driven on the highway around 80mph in hot weather (110F).
This code is triggered: 1-if the lockup torque converter LTC is stuck off, 2- LTC is stuck on, 3- LTC is slipping. I suspect 3 is the most common and shows up at high speed under load. The ECU compares the engine rpms to the trans input rpms and throws a code if they don't closely agree due to slippage in the LTC. This isn't a big deal until the LTC eventually fails to lock up / stuck off. Even then, the only impact is a small decrease in mpg, the sole purpose of the LTC. The test for a stuck off LTC is to drive the car warmed up over 50mph at a steady speed, then push down on the gas a bit, if the tach rises quickly, the LTC is Stuck off because the trans isn't locked to the engine when it should be. When the LTC goes into lock while accelerating on a highway, it feels and looks on the tach like going into a mild 5th gear.
The lockup clutch on the torque converter is hydraulically activated by a lockup valve which is apparently electrically controlled by the trans pressure solenoid valve. This solenoid valve is the one everyone zeroes in on for this code, and surprisingly, unlike the shift solenoids, it doesn't have its own electrical failure (open-short) code. If it's acting up, like sticking, it impacts shifting and causes other, more noticeable problems. If it fails, the trans won't lock up.

Anyway, the driving conditions when the CEL comes on are important to diagnosing the problem. If it looks like the LTC is acting normally, then it probably is occaissionally slipping under severe conditions. Mine was off for almost a year.
Despite the little label on my trans dipstick that says the ATF is good for life, and it looks clean, but a little brown, I plan to drain it and drop the pan. Inspect the magnets and pan for residue, clean or replace the screen and put in fresh type I-IV Toyota fluid. I may do it twice, since I'll only be getting 3 out of 8 qts each time. Hopefully, this will fix the problem if I cooked the ATF after 135k of desert driving. I could lose a lot of fuel economy before paying for a $1500 trans rebuild...

PS. there are, of course, several other failures that will throw this code. One TSB I came across for the Toyota Echo (remember Echo) pulled the transaxle and LTC, then inspected an oil seal inside the LTC that apparently keeps pressure on the lockup clutch. Fix- replace LTC. Numerous issues with the control valve body components can cause LTC malfunctions, like the famous pressure control valve solenoid. The control valve bodies in these Aisin A246E trans are surprisingly easy to remove on the car, but we won't go there.

[Newspaperman]

I am having the same issue on my 06 Vibe. The check engine light has come on 3 times in the past 2 months. I pull the battery cable and the code disappears. It happens when I drive on longer trips, usually 40 miles or more and nothing seems irregular- except the light comes on. Perplexing and bewildering for sure. The transmission seems to be shifting just fine. Have you had any luck figuring out a solution?

[TerribleTim]

I haven't changed the fluid yet, but am going on a couple road trips in Aug, so I need to do it soon.
I have not had the light come on again since.

Have you checked what code is coming up with the light?? You can get it read for free at most parts stores (except in CA). Pulling the battery cable may shut off the light, but I doubt it resets the ECU. This has to be done via the OBD port with a scan tool or by completing another drive cycle without a fault, in which case it resets itself.

[Newspaperman]

The first time it came on I checked it and it was the P0741 code. I always thought disconnecting the negative cable would reset the code? The light does goes off when I remove the cable. However, the check engine light came back on tonight after about a week or two of driving, again I removed the battery cable and the light is off for now. What I don't understand is that this problem seems to be very common, yet there is no one who has reported success with resolving it. I have a hard time believing the transmission is bad, at least on my Vibe, it shifts and accelerates smoothly, and yet I have read many reports of owners replacing the transmission due to this code. $2000 for a new transmission and it may be unnecessary?

[TerribleTim]

Yes. Like I said above, chances are it's a slight slippage in the lockup torque converter, which is no big deal. The rest of the trans is fine. At worst if the LTC stops locking up completely, your hwy mpg will drop slightly. Before LTC, all automatic trans slipped by design. The situation is that many areas(like here) have annual emission inspections which basically just scan for codes on OBD cars. If your light is lit (or if the code is still in the ecu), you flunked and can't get reregistered. If you reset the code with a scan tool, I'm pretty sure it's dumped from the ecu. I really doubt unplugging the battery does a reset. Probably just turns off the light. Easily checked though with a scan tool. After a reset, the ecu probably still has to complete a cycle before it will pass an OBD test.

The best way to check for slippage is to cruise in 4th (O/D) at 55-65mph, then push down slightly on the gas while watching the tach. If it moves up, you're slipping. If you push down hard enough, you can see the LTC unlock on the tach. Keep pushing and the trans will kick down into 3rd gear. This is real obvious with the cruise control on while driving on a hilly road because that 1.8 L motor is a little underpowered for the car and it keeps wanting to downshift. Before LTC were "perfected" they were too sensitive and would lock and unlock all the time without shifting, called hunting.

My theory is that the LTC isn't seeing enough ATF pressure to keep it from slightly slipping in hot, high speed, loaded conditions. This may be due to ATF viscosity breakdown, partially blocked filter / strainer, worn LTC seals, bad trans pressure valve. I'm going to replace the ATF and filter. If that doesn't work, I can live with it.

[Newspaperman]

Thanks Tim for your informative responses. I feel bad for those who have replaced tranny's only to have the problem reappear. Hopefully this car goes for a long time.

[TerribleTim]

Unless they got a defective rebuild, the problem should go away for at least 100K miles.

Most trans rebuilders install new, rebuilt torque convertors on this job. The LTC is the first thing that comes out after the trans is removed from the car. The issue is that no trans rebuilder is going to warranty a rebuild unless he does the trans too, especially on a car with more than say 50K miles. A big portion of the labor is just the R&R of the trans, so pulling a trans and not rebuilding it doesn't make sense.

I went thru this same scenario with a Honda years ago. The trans totally quit and when it was pulled and opened the filter was plugged. In theory, I could have told them to wash the filter and put it back together, but the car had 150K on it (Honda trans have no pan, so the filters aren't easily accessible). I spent like $1500 on a rebuild and my wife totalled the car four months later, so I didn't win on that one.
The Vibe replaced that car.

I feel bad for the folks that have to get a trans rebuilt in order to clear this code for annual inspection.
The rest of us can live with it until something more drastic happens that forces a rebuild.

[Newspaperman]

Yeah that sucks! Thankfully where I live (Minnesota) we don't have emissions testing. Just high taxes, miserable winters, and a large population passive-aggressive people .

[TerribleTim]

Finally got around to fixing this issue. My CEL kept coming on more frequently, especially on hot, highway driving and pulling trailers. Had to wait till my garage was 110F to start work :o .

Drained the fluid. Ya gotta love Toyota for not only putting a pan on this trans, but a drain plug as well. Had to take out one plastic rivet that held on the plastic bottom shield, then bend the shield back to access one of the 18 trans pan bolts in the corner. Still plenty of fluid left in the pan after draining so lower the back first. Ya gotta love Toyota for making all 18 bolts the same length. Don't even bother to drain if you don't put on at least 50 miles of hwy driving immediately before to churn up the crud into the ATF.

I bought four qts of Toyota I-IV fluid FROM THE TOYOTA DEALER. Its hard to find this rating in parts stores and I wouldn't trust / risk it anyway, even though the Toyota price is outrageous at like $5 per qt. ($15 at your ex Pontiac dealers). Got a Wix filter (mesh screen actually) from Rock Auto for like $13 includes filter and pan gaskets. Thats all it takes.

The pan and two magnets were pretty dirty with steel dust and sludge from the bands / clutchpacks, but not as bad as I expected based on other cars. The ATF was dirtier / darker than I expected while draining. Wiped out the pan and magnets real clean. I saw no evidence that the OEM filter was plugged even partially, but an autopsy remains in its future. Its held in with three bolts and the Wix and OEM both have a cork gasket glued on to seal it to the trans.

Pretty hard to screw up this job. DO NOT use gasket cement (black silicone goop) lest it gets into the trans. I cross tightened the 18 bolts til just snug, then went around in about three rotations to gently torque them down. (hey, I like laying on my back, even in 110F). DO NOT OVERTIGHTEN. The only way to screw this job up is to overtighten the pan and crush and split the rubber gasket causing a leak. Put the plastic rivet back in and down 4 qts Type I-IV ATF with beer chaser. Check fluid level per the owners manual.

Bottom line- put on about 1500 hwy and city driving so far. The CEL came on once during the first 100 miles,reset and hasn't been on since. I am officially declaring victory.

As far as why this worked, my theory is that the filter apparently had little to do with it in terms of pressure drop from being plugged with sludge because it looks clean and theres a lot of mesh area. Best guess is that the ATF was either broke down and low viscosity was causing low pressure and slippage at lockup, or ATF was dirty and contaminated with worn friction material from the trans causing the lockup clutch to slip. The trans does seem to shift better and be generally happier. Also, the new fluid apparently took 100 miles to wash out the crud that was causing the slip since the CEL came on once. I give about an 80% chance that I could have gotten the same result without dropping the pan and just changing the ATF after churning it up. Pretty cheap to do it right yourself tho. But a Meineke, etc. could do a fluid change in a few minutes cheap, just bring them the Toyota fluid and don't let them hook it up to the flush machine. These Aisin trans are pretty tempermental. Oh, and ignore that little sticker on the trans dipstick that says the fluid is good for life.

[TerribleTim]

Update-
On the return road trip, total trip about 2500 miles, code p0741 came up three times within 200 miles in exactly the same way. Pulled off the freeway for gas,food,pit stop, etc. turned the car off for 15-30 min and then went back onto the fway ramp within 1/4 mile. I don't accelerate real hard on a ramp, especially when loaded with passengers and luggage. When the torque converter went into lockup at the bottom of the ramp, the CEL with this code came up each time. Didn't come on if I never turn off the engine and hit the ramp. Harder acceleration and o/D button seemed to make no difference- no CEL.

when I got back, I rechecked the ATF level per the manual several times and it was the same as before the road trip at the center of the bottom cold notch. IOW it was still slightly low. Picked up another qt of type T-IV from the Toyota dealer (now $6.50 / qt) and put in 16 oz (half - one pint). After rechecking level several times, it rose to the center of the top hot notch. NB bottom to top notch is 16 oz. no CEL after those three-in-a-row about 600 miles ago. Hoping the code showed up because of low atf.

Assuming that since the CEL only came on when the car was off for 15-30 min, then went right onto hwy, its a pressure problem due to low atf level, and high load on the lockup clutch cylinder before the fluid pump could reach full pressure under these exact conditions. Pure speculation.
Adding another half qt of clean, fresh atf can't hurt either.

Will update if problem returns. I get no CEL just driving around town, even on-off hwy.
Bottom line- after a trans drain and filter replacement, add 4.5 quarts Toyota type T-IV to get the correct atf level.

[circuitsmith]

TerribleTim I'd drain and refill the fluid again since a 4.5qt change leaves about 1/2 the old fluid in the system.

[TerribleTim]

Tnx.
Yes, I realize half the atf is stll in the torque converter after you drain the pan, so each 4.5 qt drain and refill ($40ea) dilutes the contaminents 50%. when do I quit?. The fluid looks real good on the dipstick after my one drain, and it has reduced the code to essentially none.

Update- after I added the last half qt, the CEL has stayed off, EXCEPT one time again when I was accelerating on a highway ramp after the engine had been off for 5 minutes and the trans was still hot. Since, I accelerate onto highway ramps all the time without a CEL now, the problem appears to be 95% fixed. It was coming on all the time even in around town driving before I changed the atf and filter.

The last 5% could be fixed by draining and refilling the atf again as Circuitsmith suggests, but I'm living with this now. It's 110F outside and I'm also curious how the trans acts in the Phx 'winter.'

I have not looked at an exploded diagram of this trans or gutted one, so I don't know the exact mechanism of the LTC, but the slippage causing P0741 is low pressure on the friction pad in the torque converter probably due to wear of the friction material (hey, mine has 140Kmi on it) or worn or leaking seals on the actuator for the friction pad. A cheap replacement of just the torque converter (which still requires dropping the trans) would fix it, but not recommended unless the rest of the trans has very low miles since dropping the trans is the hard part, labor wise. Strictly for DIYers. If changing atf and filter doesn't help, a new torque converter is needed and with many miles, a trans rebuild while its off. Not cheap. Although like I said, this is really a non problem. You could probably put another 100Kmi on the car and trans with the CEL on and never notice a thing different. The only time its an issue is if you need the CEL off for an inspection. Just remember to check for other codes occaissionally that the p0741 might be hiding with the CEL on

The most important thing is to do some high speed and around town driving before you drain the atf so the dirt, etc. gets suspended in the fluid (this doesn't last long) and comes out with the fluid. It makes the job a lot hotter, but it's the only proper way.

Did I mention this is my wife/daughters car and every car I've ever owned/driven has been a stick...

[maximumvibe]

Tnx.
Yes, I realize half the atf is stll in the torque converter after you drain the pan, so each 4.5 qt drain and refill ($40ea) dilutes the contaminents 50%. when do I quit?. The fluid looks real good on the dipstick after my one drain, and it has reduced the code to essentially none.

Update- after I added the last half qt, the CEL has stayed off, EXCEPT one time again when I was accelerating on a highway ramp after the engine had been off for 5 minutes and the trans was still hot. Since, I accelerate onto highway ramps all the time without a CEL now, the problem appears to be 95% fixed. It was coming on all the time even in around town driving before I changed the atf and filter.

The last 5% could be fixed by draining and refilling the atf again as Circuitsmith suggests, but I'm living with this now. It's 110F outside and I'm also curious how the trans acts in the Phx 'winter.'

I have not looked at an exploded diagram of this trans or gutted one, so I don't know the exact mechanism of the LTC, but the slippage causing P0741 is low pressure on the friction pad in the torque converter probably due to wear of the friction material (hey, mine has 140Kmi on it) or worn or leaking seals on the actuator for the friction pad. A cheap replacement of just the torque converter (which still requires dropping the trans) would fix it, but not recommended unless the rest of the trans has very low miles since dropping the trans is the hard part, labor wise. Strictly for DIYers. If changing atf and filter doesn't help, a new torque converter is needed and with many miles, a trans rebuild while its off. Not cheap. Although like I said, this is really a non problem. You could probably put another 100Kmi on the car and trans with the CEL on and never notice a thing different. The only time its an issue is if you need the CEL off for an inspection. Just remember to check for other codes occaissionally that the p0741 might be hiding with the CEL on

The most important thing is to do some high speed and around town driving before you drain the atf so the dirt, etc. gets suspended in the fluid (this doesn't last long) and comes out with the fluid. It makes the job a lot hotter, but it's the only proper way.

Did I mention this is my wife/daughters car and every car I've ever owned/driven has been a stick...

Hello all, just wanted to introduce myself as a new owner of a 2005 Pontiac vibe with 108,000 miles. Great forum with lots of good info here!

I made this account specifically to thank TerribleTim for his post, it was a great help in diagnosing my own issues with P0741. We started receiving the code during longer periods of highway driving (30 min or more at 60+ mph). This started the typical "oh crap did we buy a car with a bad transmission" freakout. I should also mention this is my girlfriends car and we are both graduate students.

Decided to go the cheaper route first and just purchase a case of T-IV AT fluid from the Toyota dealership (paid $65 for 12 quarts!!) and now I have been swapping it out every 500 or so miles with the simple pull the plug and drain whatever fluid is in the pan method (about 3-4 quarts each time). Noticed that shifts have smoothed out dramatically and the P0741 code seems to be staying away, so I am hoping it was likely just dirty fluid. Will update in time if any other issues arise.

Thanks again everyone!

Cheers,

Mark