Page 10 of 10 FirstFirst 12345678910
Results 91 to 98 of 98
  1. #91
    Join Date
    Jun 2013
    Location
    Northeast
    Posts
    582

    Default

    Thanks for the info, FirstVolvo. The storm in the Northeast hit us hard; it's been a few days without power and tree branches down everywhere.

    Car is still throwing the P0740 code and going into limp mode, with and without the MAF sensor connected. I'm still getting the engine speed=6000 rpm frozen value. The last time it happened I was in 5th gear doing around 50mph and I saw the VIDA readout for engine speed actually say "6000" and a couple seconds later the car went into limp mode. My actual rpms according to the tachometer was around 2000.

    This is going to take some time and patience on my part to continue to gather data, make some educated guesses, and try some different things. Again, this car doesn't see a lot of use so I'm going to relax, take a step back, and just use the car around town for the time being til I can figure out what's what.

    As for whether the trans is locking up in 5th gear - yeah, I think it is. It definitely doesn't seem to be slipping or downshifting into 4th when accelerating gradually at highway speeds. I'm not doing a lot of hard driving at 55+ so maybe I'm not putting the TCC thru its paces to test the lockup function. All indications in the VIDA readout show no anomalies until a 6000 pops up in the engine speed rpm and then P0740 code.

    FirstVolvo, I'm definitely looking into other factors such as sensors which impact TCM behavior. It's just gonna take me some time to work thru the different possible causes for that 6000 rpm engine speed value. The engine speed reported by VIDA follows closely the tachometer reading until it changes to 6000.

    Thanks everyone for your support and guidance! When I feel like I have an answer for this code, I'll update this thread.
    2007 XC70, 206,000 miles
    2002 V70XC, 130,000 miles, parts car

  2. #92
    Join Date
    Jan 2009
    Location
    Sacramento, CA
    Posts
    160

    Default

    Xfingers, I still think there may be a solution to your P0740 problem based on a couple of things. You werenít getting the P0740 code with the old valve body and the possibility of the code being set by an incorrect 6000 engine RPM value. I just donít think the torque converter clutch suddenly went bad and started slipping after the new valve body replacement, which is worse case and a possibility but not probable.
    The P0740 code is a very specific test comparing the engine RPM to the transmission input shaft RPM and must be within 200 RPM of each when the torque converter clutch is locked or you get the code from what Iíve read.
    ATF contaminated by water could cause this code so hopefully the flush you did got rid of all the water.
    What needs to be known is if the code is being caused by the TCC actually slipping or is the code being set because a bad engine RPM value (the 6000 RPM value) is being used and compared to the correct and much lower input shaft RPM.
    To determine if the TCC is actually slipping Iím thinking if you drove on level ground or slightly downhill for as long as possible and at a speed when the TCC is locked and as gently as possible on the gas pedal I wouldnít expect you to see a P0740 code. Basically put no stress on the locked TCC for as long as possible. If you do see the P0740 code under the low stress condition and you see the 6000 RPM value pop up then I would think the code is being set because the engine RPM value is incorrect.
    Like you mentioned the 6000 RPM value may be a substituted value but then the question is whatís going on that would require the actual engine RPM value to be a substitute value. A bad signal from the crankshaft position sensor could be a possibility but I would expect there to be other problems and codes if this were occurring. On the other hand if there was a short, intermittent type problem with the CPS signal maybe this would cause the problem youíre seeing. The 6000 RPM and 500Nm torque values you captured in the freeze frame data sure does look like upper limit default substitute values.
    There are other possible problems with the TCC (SLU) solenoid that could set this code but you mentioned the TCC does appear to be locking when driving the car and monitoring the RPM.
    Iím most suspicious of the RPM and torque freeze frame values indicating a different problem than the torque converter or valve body.
    One question, you said you saw the 6000 RPM value pop up before the code was set, was this live data when you saw the 6K RPM value pop up or freeze frame data?

  3. #93
    Join Date
    Jun 2013
    Location
    Northeast
    Posts
    582

    Default

    Quote Originally Posted by FirstVolvo View Post
    What needs to be known is if the code is being caused by the TCC actually slipping or is the code being set because a bad engine RPM value (the 6000 RPM value) is being used and compared to the correct and much lower input shaft RPM.
    I agree FirstVolvo. This is what I'm trying to determine. I'm not a programmer and don't have access to the software code but what data is the TCM seeing that makes it throw the P0740 code and go into limp mode? If it's comparing a 6000rpm engine speed with an input shaft rpm of 2000, then can anyone blame it for thinking lockup isn't working and something's drastically wrong? On the other hand, when the TCM becomes aware that lockup is not fully engaged (slipping) in 5th, does the TCM itself generate the 6000rpm value for engine speed as its way of triggering limp mode? I haven't found a lot of info on 6000rpm engine speed but I'm thinking it must be computer-generated. When a sensor is failing, does it give erratic values, no values or a value of 6000?

    Quote Originally Posted by FirstVolvo View Post
    To determine if the TCC is actually slipping I’m thinking if you drove on level ground or slightly downhill for as long as possible and at a speed when the TCC is locked and as gently as possible on the gas pedal I wouldn’t expect you to see a P0740 code. Basically put no stress on the locked TCC for as long as possible. If you do see the P0740 code under the low stress condition and you see the 6000 RPM value pop up then I would think the code is being set because the engine RPM value is incorrect.
    When I'm driving 55mph on level ground I don't get the code until I go up a slight incline. I live in the foothills of the Catskills so there's not a lot of flat terrain. If I'm accelerating up the incline, no code. If I pull my foot completely off the gas (this disables lockup, voltage to SLU drops), no code. If my foot is stationary on the gas pedal and a slight grade, that triggers the code. It almost feels like when you would expect the trans to downshift to 4th, instead you get a code. In fact, this fall the car would downshift in these situations. My research indicates this is a known condition but no one seems to have found a definitive solution. On my regular drives, I'm aware of the inclines in the routes which will trigger limp mode. I'm thinking of putting the trans in 4th geartronic on these sections. [/QUOTE]

    Quote Originally Posted by FirstVolvo View Post
    I’m most suspicious of the RPM and torque freeze frame values indicating a different problem than the torque converter or valve body.
    One question, you said you saw the 6000 RPM value pop up before the code was set, was this live data when you saw the 6K RPM value pop up or freeze frame data?
    This was live data. I glanced at the screen, saw 6000rpm, and sure enough seconds later limp mode. I'm still compiling data, doing research and checking into possibilities. VIDA indicates that limp mode can be triggered by various ECM components - not just the TCM. More data: I tried driving in Cruise Control on the 45+ mph sections. Again, this is hilly terrain and the cruise was really kicking in with some heavy accelerations, harder than I drive the car. Although the trans handled sections with no problem where I would have expected limp mode, ultimately it did go into limp but this time it threw the old code, P0735 (5th gear, incorrect ratio). Unfortunately, I cleared the code with a simple code reader before looking at the frozen values in VIDA.

    I'm having a hard time believing that the P0470 code is a new problem that surfaced after the VB replacement. Mainly because the symptoms are the same. 45+ mph going up an incline. Originally I would only get this code going up the steep mountain pass to the ski resort. Now limp mode seems to be triggered on any significant incline. My best guess is whatever is failing on the car, it's gotten worse. Maybe it is wear on the TCC but the car drives great. You'd never guess there's a problem until you lose gears and now the car is in limp mode.

    There's still some things I want to investigate. It's gonna take some time to rule out the different possibilities. We're due for a foot of snow today.
    Last edited by Xfingers; 03-07-2018 at 08:09 AM.
    2007 XC70, 206,000 miles
    2002 V70XC, 130,000 miles, parts car

  4. #94
    Join Date
    Feb 2010
    Location
    Virginia Beach
    Posts
    4,082

    Default

    Did you get clean fluid in this?

    All the programming speculation in the world is meaningless if the fluid is still contaminated.
    Current Fleet:
    2016 Tundra Crewmax 4WD 1794
    2005 MB S600 (114K, Michelin AS3+, LiquiMoly 0W40)
    2005 MB SL600 (50K, Michelin AS4, Mobil 1 0W40)
    2004 V70R (six speed M66, Mobil 1 5W30)
    2002 V70-XC (275K, HPL Euro 0W30)
    2002 V70-T5 (216K, IPD bars, Bilsteins)
    2001 V70-T5 (120K, IPD downpipe, cat back and other mods)
    1932 Packard Sedan (straight 8, dual sidemounts, original paint and interior, Shell Rotella 15W40)

  5. #95
    Join Date
    Jun 2013
    Location
    Northeast
    Posts
    582

    Default

    The pink milkshake stuff was in there for about two test drives, maybe 15 miles total. I flushed with 12 qts. of Aisin 3309 and the last fluid coming out was cherry red. I'm not losing any coolant. I agree it's hard to tell the quality of the ATF by looking at the dipstick. I don't think I have contaminated fluid because the shifting is very smooth now. On the two test drives with the milkshake ATF, the shifting was a little jerky and rough. I noticed the improved shift quality immediately with the new fluid. I'm thinking if this fluid becomes contaminated, the shifts will deteriorate. What I'd really need to do to know for sure is get under the car and drain out a little ATF from the plug.
    2007 XC70, 206,000 miles
    2002 V70XC, 130,000 miles, parts car

  6. #96
    Join Date
    Jan 2009
    Location
    Sacramento, CA
    Posts
    160

    Default

    Based on the driving conditions you mentioned and when you see the code and then limp mode it does sound like the torque converter clutch is slipping. The P0735 5th gear ratio incorrect code may also be associated with the torque converter if the gear ratio calculation is expecting a TCC lockup condition, which I didn't expect. Here's a link with some information about a torque converter replacement to solve a P0735 code.

    Not sure about the accuracy of all this, just some added information about a similar problem
    http://forum.e46fanatics.com/showthread.php?t=1065889

    Here some information about a Volvo P0740 code what it took to eliminate the problem, a new torque converter and trans pump plate work.
    https://www.matthewsvolvosite.com/fo...ic.php?t=74421

    One thing you might consider to help confirm if itís the TCC is slipping is to add Lucas transmission fix additive. I realize this is not a permanent fix and likely won't eliminate the codes you're seeing but I think there's value in knowing if this additive reduces the number of times the codes are set and it won't hurt anything other than requiring the cost and time another flush to remove it later. The additive is supposed to help seal leaks and reduce slippage from worn bands. If after adding the additive and the codes donít show up as often then I think it would confirm thereís TCC slippage occurring and the problem is not associated with a bad engine RPM value being used to set the code. If under similar driving conditions thereís no change in the frequency of the codes set and limp mode then the problem is likely not TCC slippage and you could do another flush to remove the additive if needed.

    Something I donít understand with Volvo software (and probably others), is why it goes into limp mode for the TCC slipping, why not just disable the TCC, set the code and light but not limp mode. Yes, gas mileage will suffer until fixed but as long as the ATF temperature isnít out of control limp mode isnít needed in this case in my opinion.

  7. #97
    Join Date
    Feb 2010
    Location
    Virginia Beach
    Posts
    4,082

    Default

    A torque converter that is supposed to lock will create a TON of heat if it is unlocked. The factory cooling will not keep up. A few long uphills on the highway and it will overheat the transmission.

    So, it goes into limp mode.
    Current Fleet:
    2016 Tundra Crewmax 4WD 1794
    2005 MB S600 (114K, Michelin AS3+, LiquiMoly 0W40)
    2005 MB SL600 (50K, Michelin AS4, Mobil 1 0W40)
    2004 V70R (six speed M66, Mobil 1 5W30)
    2002 V70-XC (275K, HPL Euro 0W30)
    2002 V70-T5 (216K, IPD bars, Bilsteins)
    2001 V70-T5 (120K, IPD downpipe, cat back and other mods)
    1932 Packard Sedan (straight 8, dual sidemounts, original paint and interior, Shell Rotella 15W40)

  8. #98
    Join Date
    Jun 2013
    Location
    Northeast
    Posts
    582

    Default

    I think I'm gonna be taking it for a drive tomorrow. There's a few ECM parameters I want to monitor as well as TCM. As far as the TCC slipping, at higher mph (50+) more fluid pressure is required to maintain lockup? I can drive in 5th gear with no problems at 35-45 mph.

    Power just went out again so time to shut down the computer.
    2007 XC70, 206,000 miles
    2002 V70XC, 130,000 miles, parts car

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •