CVT Slipping?

[DjAnnexAlpha]

Hey everyone. Today I was at a red light, light turned green, I slowly got up to 20mph and then it wouldn't go up any higher for like 10 seconds until I let go of the gas and pressed on it again. It hasn't happened since. A quick google search shows me that there are NO other topics regarding this new CVT. I hope that there really is no problem with the CVT. Thoughts?

 

[Donabed Kopoian]

Did the engine rev higher but the car stayed at the same speed?

 

[Scott O'Kashan]

DjAnnexAlpha - The car seems to be giving you some real problems.

 

[DjAnnexAlpha]

Did the engine rev higher but the car stayed at the same speed?

No, the engine stayed on the same RPMs and the same speed.

 

[DjAnnexAlpha]

DjAnnexAlpha - The car seems to be giving you some real problems.

Yeah...my moms 09 camry has 60k miles on it and the only issue it had was the cd player in the radio not working :laughing:

 

[Donabed Kopoian]

If the belt was slipping the engine would rev higher while the car maintained speed. Sounds like the drive-by-wire system had a small hiccup.

 

[DjAnnexAlpha]

If the belt was slipping the engine would rev higher while the car maintained speed. Sounds like the drive-by-wire system had a small hiccup.

Here is hoping that it was only a small hiccup. Unfortunately I cannot find any reading material regarding warning signs of a troubled CVT.

 

[rondunc]

Hopefully that means the CVT is a dependable transmission.

 

[Donabed Kopoian]

It has nothing to do with your CVT. It's a drive-by-wire issue.

CVT belt slipping would be the same as a clutch slipping on a car (and would probably make a pretty horrid noise, but theoretically it shouldn't ever slip since the ratios are controlled by solenoid, and the belt will always have tension no matter what by design of the CVT).

Failing to shift, the car getting stuck in a specific gear, manual mode failing to function, that's CVT issues.

 

[Donabed Kopoian]

Basically, if the drive-by-wire system loses track of the throttle pedal position because of a dead spot in the potentiometer, or sees a reading that doesn't make sense, it will hold throttle position as a fail-safe. Getting off the gas and getting back on it resets it.

If it happens again, you may have a failing throttle pedal position sensor.

 

[Scott O'Kashan]

Also the possibility that a hacker hacked into the cars computer system. I've read this is an increasing threat, where a hacker can get into a cars computer system and disable the brakes, shut off the engine, etc., etc. I'm sure there's nitwits out there that think doing this would be, "fun". :thumbdown:

 

[rondunc]

Basically, if the drive-by-wire system loses track of the throttle pedal position because of a dead spot in the potentiometer, or sees a reading that doesn't make sense, it will hold throttle position as a fail-safe. Getting off the gas and getting back on it resets it.

If it happens again, you may have a failing throttle pedal position sensor.

Let's pretend you throttle 100% and it gets a "reading that doesn't make since" so it holds that reading until it can reset. That sounds like the whole Prius issue all over again.

It would make more since to drop throttle to 0% until a reset can accure.

 

[Scott O'Kashan]

rondunc - That's a very good thought. :thumbsup:

 

[DjAnnexAlpha]

Basically, if the drive-by-wire system loses track of the throttle pedal position because of a dead spot in the potentiometer, or sees a reading that doesn't make sense, it will hold throttle position as a fail-safe. Getting off the gas and getting back on it resets it.

If it happens again, you may have a failing throttle pedal position sensor.

That is exactly how I corrected it! When I noticed the issue I got off the peddle then back on it and ever since then it was fine.

 

[DjAnnexAlpha]

Also the possibility that a hacker hacked into the cars computer system. I've read this is an increasing threat, where a hacker can get into a cars computer system and disable the brakes, shut off the engine, etc., etc. I'm sure there's nitwits out there that think doing this would be, "fun". :thumbdown:

For something like to that occur to a corolla I would need to have that close proximity sensor. Theoretically, a hacker can follow me around all day and whenever I unlock my car attempt to intercept my key fob code but that would be unlikely...all for a corolla? lol

 

[Scott O'Kashan]

The hackers get into your cars onboard computer via the TPMS, (Tire Pressure Monitoring System), sensors and the signals they transmit.

 

[Donabed Kopoian]

Also the possibility that a hacker hacked into the cars computer system. I've read this is an increasing threat, where a hacker can get into a cars computer system and disable the brakes, shut off the engine, etc., etc. I'm sure there's nitwits out there that think doing this would be, "fun". :thumbdown:

Not possible, unless they cut into your wiring harness and added a wireless system that would allow them to trick the PCM ... but for all of that effort, if anything, would be to target the car of a bank owner or something like that (and is more likely the plot of a really bad movie). The PCM is a closed-circuit system. The only circuit that is wireless, that a hacker could access, would be the remote alarm system.

 

[Donabed Kopoian]

Let's pretend you throttle 100% and it gets a "reading that doesn't make since" so it holds that reading until it can reset. That sounds like the whole Prius issue all over again.

It would make more since to drop throttle to 0% until a reset can accure.

When you let off the throttle, it resets ;-)

Also, I believe Toyota implemented a system that if the gas and brake are pressed at the same time, the engine shuts down, but don't quote me on that.

 

[Donabed Kopoian]

The hackers get into your cars onboard computer via the TPMS, (Tire Pressure Monitoring System), sensors and the signals they transmit.

Hacking the TPMS circuit would only affect the tire pressure monitoring system. The rest of the circuits are separate. Car PCM's are real-time systems, the circuits must be kept separate and bandwidth as high as possible to keep the polling rate that is required for these engines to run efficiently, especially when signals can cycle in the Kilohertz range.

 

[TigerHeli]

I agree - it is PROBABLY a drive-by-wire, throttle position sensor issue, but this also isn't a conventional CVT.

If the CVT didn't get the signal to drop to the next "virtual" gear, couldn't the same issue occur?

 

[Scott O'Kashan]

Hackers Find Weaknesses in Car Computer Systems

http://www.foxnews.com/leisure/2013/09/04/hackers-find-weaknesses-in-car-computer-systems/

 

[Donabed Kopoian]

I agree - it is PROBABLY a drive-by-wire, throttle position sensor issue, but this also isn't a conventional CVT.

If the CVT didn't get the signal to drop to the next "virtual" gear, couldn't the same issue occur?

He said he added throttle but the car maintained speed, so if that was the case, the car would have accelerated and not shift into the next gear.

 

[Scott O'Kashan]

Hackers Reveal Nasty New Car Attacks--With Me Behind The Wheel (Video)

http://www.forbes.com/sites/andygre...w-car-attacks-with-me-behind-the-wheel-video/

 

[Donabed Kopoian]

Hackers Find Weaknesses in Car Computer Systems

http://www.foxnews.com/leisure/2013/09/04/hackers-find-weaknesses-in-car-computer-systems/

The hacks they talk about (slamming the brakes and jerking the steering wheel) were local network hacks (meaning via a laptop connected to the OBD-II port, and those were vehicles equipped with lane assist and crash-detection automatic braking systems).

I'm sure they got into the system with Bluetooth through the stereo and through the TPMS systems, but there isn't much damage you can do through there except delete my radio presets, change my auto-lock/unlock settings, or trigger my car into thinking I have a flat.

It would take a very poorly designed system to allow full and total control of a vehicle wirelessly, and it would be a miracle if it was efficient having all of these parts on one data bus (which is what makes personal computer systems prone to hacking, but easier to program).

 

[Donabed Kopoian]

Hackers Reveal Nasty New Car Attacks--With Me Behind The Wheel (Video)

http://www.forbes.com/sites/andygre...w-car-attacks-with-me-behind-the-wheel-video/

This again was with a direct link to the car.

They also reverse-engineered the PCM's software in order to do this. This requires a thorough knowledge of computer programming concepts and computer language, as well as de-compiling software that requires a full logical trace run in order to be accurate, usually done with a scripting language.

This isn't something that a common thug or prankster will have the knowledge to do.

 

[DjAnnexAlpha]

He said he added throttle but the car maintained speed, so if that was the case, the car would have accelerated and not shift into the next gear.

At the time I gave the car a steady amount of gas BUT the rpms and mph stayed the same for like 10 seconds until I got off the gas and pressed on it again.

 

[tylerwatt12]

how many seconds from the light turning green were you when you noticed this?

If you have the S model it's possible you were stuck in a gear for a few seconds.

 

[DjAnnexAlpha]

how many seconds from the light turning green were you when you noticed this?

If you have the S model it's possible you were stuck in a gear for a few seconds.

I have the CVT transmission. I have been told that it might also relate to the sensor in the pedal.

 

[tylerwatt12]

I have the CVT transmission. I have been told that it might also relate to the sensor in the pedal.

I have the CVT as well. I meant the simulated gear when in sport mode.