So the system is not just looking for the electrical brake light switch to make, it is looking for some specific hydraulic pressure to allow activation. Wonder why? Oh well.
Brand New 2022 CX-5 Transmission Problems? Updated!
- Thread starter Guy41
- Start date
It has to do with the clutch cycling, it can physically move the car so for safety it is programmed that way.
@sinistriel@ Thank you for your great video. I found and tried it because I have a rather strange issue (it's not really a problem, but I find it kind of weird) with my CX-5 2.5 G-194 AWD AT 2020, Europe, non-turbo, 70.000km. On the highway, once it is warm (during winter, it takes longer until it happens), every like 2-3 minutes the RPMs go 2-300RPMs higher for like 5s in the 6th gear, and then fall back to normal, lacking any comprehensible reason. The highway is completely flat for dozens of kilometers, it even happens while driving downhill. There are no strong winds, there is no other traffic. It happens with and without Cruise Control, also in M mode, with A/C off, iStop off, etc. etc. Mazda dealer has never heard about it, can't really find anything but didn't really believe me I think. He made a short test cruise not on the highway changing through gears and said there is minimal slippage on the clutch, but it's okay. There are no error codes, so he could not do more. Don't think that was really a relevant test, because I don't have constant issue, but a recurrent one under circumstances he didn't have time for.
I made a video some months ago for a European forum, nobody here has heard about it before and nobody really has a clue:
youtu.be
I can't really find anything similar to my issue. Am I the only monk noticing that? I don't really find that behaviour normal. You can also feel a short jerk in the powertrain. First I thought about Cylinder Deactivation, I can also feel a short jerk with CD, but I think the parameters are not fulfilled for CD on a highway.
Since my video, I added OBD and forscan to the mix. I found that the TCM slip value is very high during those events, the android app crashed when I stopped my car, so I couldn't save the data and look at the other TCM values. I have to repeat it. Most likely, I might find what I was suspecting for a long time: The torque converter lockup-clutch (I mean the clutch that bypasses the torque converter when a fixed transmission of force is required and possible) opens up, causing slippage. But why, for gods sake, every couple of minutes? What is it still trying to measure or learn?
I thought maybe resetting the learned values might help and found your video. It worked fined at first try, motor revving up in the end. I noticed a sudden difference in the TCM's actions, but the issue with frequently increased RPMs in 6th gear stayed the same. On the other hand, it how has to learn again, but I would be amazed if it stops that annoying behaviour in the near future.
Do you have any idea why the TCM is doing what it is doing? Ever heard about such strange issues with Mazda ATs?
I made a video some months ago for a European forum, nobody here has heard about it before and nobody really has a clue:
VID 20230927 160313
youtu.be
I can't really find anything similar to my issue. Am I the only monk noticing that? I don't really find that behaviour normal. You can also feel a short jerk in the powertrain. First I thought about Cylinder Deactivation, I can also feel a short jerk with CD, but I think the parameters are not fulfilled for CD on a highway.
Since my video, I added OBD and forscan to the mix. I found that the TCM slip value is very high during those events, the android app crashed when I stopped my car, so I couldn't save the data and look at the other TCM values. I have to repeat it. Most likely, I might find what I was suspecting for a long time: The torque converter lockup-clutch (I mean the clutch that bypasses the torque converter when a fixed transmission of force is required and possible) opens up, causing slippage. But why, for gods sake, every couple of minutes? What is it still trying to measure or learn?
I thought maybe resetting the learned values might help and found your video. It worked fined at first try, motor revving up in the end. I noticed a sudden difference in the TCM's actions, but the issue with frequently increased RPMs in 6th gear stayed the same. On the other hand, it how has to learn again, but I would be amazed if it stops that annoying behaviour in the near future.
Do you have any idea why the TCM is doing what it is doing? Ever heard about such strange issues with Mazda ATs?
A couple things it could be. First, normal behavior that happens industry wide and not Mazda specific. Second, the torque converter clutch lining is wearing and at low pressure application it can't hold correctly. The easy way since you have Forscan is to see what the pressure being commanded to the TCC is, if the pressure lowers when the revs increase you know the TCC is being commanded to open and is considered normal operation.I made a video some months ago for a European forum, nobody here has heard about it before and nobody really has a clue:
VID 20230927 160313
I can't really find anything similar to my issue. Am I the only monk noticing that? I don't really find that behaviour normal. You can also feel a short jerk in the powertrain. First I thought about Cylinder Deactivation, I can also feel a short jerk with CD, but I think the parameters are not fulfilled for CD on a highway.
So that leads us to reason why it's being commanded to operate like this. TCC application is very load dependent. Many OEMs will have a converter unlock when a load inside the vehicle changes vs having the vehicle downshift. This allows some torque multiplication and is often enough to keep the vehicle moving at the same rate of speed without having to shift down to the next gear provided the load is only slightly higher than what it was.
From what I can see from your video it looks like common Skyactiv behavior.
Thanks for your thoughts! As mentioned, there is absolutely no change in load by the environment or any internal consumers I can influence (A/C etc.). It even does this when going downhill a soft slope. It does NOT do it many many times when going up a soft slope. It also happens without CC, when I just keep the RPMs constant manually or rather per pedes. If there would be a change in load, speed would likely drop. Same in M mode. The only variable I observed is that in winter, it takes longer on the highway until this frequent behaviour starts (rather 10-15min than 5-10m in summer). Then, every 2-3min it happens.
I think I will just record all TCM PIDs and have a look at them. So if I understand correctly, if the commanded pressure does NOT go down when or before the slippage and RPM increases, but maybe the actually measured pressure (not sure if this PID exists, I saw a couple of commanded vs. measures value couples) goes down, then this is NOT desired or commanded by the TCM, the TCM would only react, and it needs further thought?
I think I will just record all TCM PIDs and have a look at them. So if I understand correctly, if the commanded pressure does NOT go down when or before the slippage and RPM increases, but maybe the actually measured pressure (not sure if this PID exists, I saw a couple of commanded vs. measures value couples) goes down, then this is NOT desired or commanded by the TCM, the TCM would only react, and it needs further thought?
Load on the vehicle side can change imperceptibly to an occupant and can be triggered by something as simple as the alternator being commanded to provide more charging.
For the commanded vs actual slip what you want to look for is when the slip occurs if there was a commanded change in the pressure to the TCC. If there was a commanded change then you're fine and nothing to worry about, if the slip occurs with no commanded change then you have a mechanical issue that is developing. TCM will command more pressure to the TCC to hold the clutches tighter, releases pressure to allow slip or to unlock. You'll see it is pretty active as Mazda does slip the TCC a fair amount.
