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DanniEl

Yaris 1.3 mmt auto jerking when start moving

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Hello everyone! 

I have recently bought  Yaris Zinc 1.3 2007 MMT automatic transmisson and found a problem that bothers me a lot.

When I start moving forward or backward (especially slowly) car jerks. When I add more gas and accelerate sharply jerking is gone, it is also fine when the engine is hot. 

Now, I have read quite lot about jerking and mmt but I could not find some answers so I want to ask :

1. Would initialisation of ECU and clutch help? 
2. Is this really transmission problem? 
3. Would tranny Oil change help?
4. In case of changing transmission do I need to buy whole new transmission or just some part (which is gone) and what are the aprox. prices of it ? (I am starting at Uni shortly and thus have very limited budget.) 

Thank you all for your help and advices.

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Does your car creep on its own when releasing the brake pedal and without pressing the throttle? if no then your transmission needs reinitialising 

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It's not a true automatic, it's a 'manual' gearbox and clutch with electric actuators and a computer to replace the driver in operation of the clutch and gears. So changing the Oil is unlikely to help.

It's most likely a problem with the clutch. As Devon says, reinitialising it may help. However, as it's a normal mechanical clutch it may simply be worn out. You don't say how many miles or what sort of use it may have had before you got it, so that info would help.

I will mention that ours (a 1.4D MMT) also can sometimes be a bit sudden when cold, but that is sorted within a hundred yards, so yours does sound excessive.

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10 hours ago, Devon Aygo said:

Does your car creep on its own when releasing the brake pedal and without pressing the throttle? if no then your transmission needs reinitialising 

No it doesnt, I have found more info about the reinitialising and try it tomorrow.

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5 hours ago, MikeSh said:

It's not a true automatic, it's a 'manual' gearbox and clutch with electric actuators and a computer to replace the driver in operation of the clutch and gears. So changing the oil is unlikely to help.

It's most likely a problem with the clutch. As Devon says, reinitialising it may help. However, as it's a normal mechanical clutch it may simply be worn out. You don't say how many miles or what sort of use it may have had before you got it, so that info would help.

I will mention that ours (a 1.4D MMT) also can sometimes be a bit sudden when cold, but that is sorted within a hundred yards, so yours does sound excessive.

Currently 80k, it is category D and the previous owner said to me that the car has not been used over a year. He just bought a new car and kept the old one in the garage with the vision of fixing the paintwork and other minor damages, but he better sold it eventually.

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Wohouu !! Problem solved and it was unbelievable easy. I have initialised ECU and Clutch and car drives like a new. Thank you all !! 

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Brilliant. Thanks for letting us know.

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Hi DannEI 

I've just written a very similar post looking for info.
In my case, the front crawl works fine. The problem is reversing. It won't crawl. A little accelerator and it jerks backward initially. 
wondering if a software ECU reinitialisation is needed. Did you do this at a Toyota Dealership or can any dealership do it?

Thanks
Jud

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I just bought a Toyota yaris 2006 model dual gearbox (automatic and manual gears). It jerks so much when i gas from a stationary position and when reversing. I'm told that's how toyota dual gear works and the jerking is normal. 

Does anyone has an idea if this is true? or has knowledge on what I can do? Thanks in advance!

Hen.

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3 minutes ago, Henby said:

dual gearbox (automatic and manual gears

This would be the Multi Mode Transmission. Rather than a 'dual gearbox', it is a manual with automated clutch.

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12 minutes ago, Henby said:

I just bought a Toyota yaris 2006 model dual gearbox (automatic and manual gears). It jerks so much when i gas from a stationary position and when reversing. I'm told that's how toyota dual gear works and the jerking is normal. 

Does anyone has an idea if this is true? or has knowledge on what I can do? Thanks in advance!

Hen.

No, it's not normal to have rough starts like that.

Was it a private seller, or a dealer you bought it from?

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private

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Its normal tbh unless its awful like a being hit from behind or a learner driver learning clutch control, has it had a clutch in its life ?

I take it you're using 1 foot for the throttle and brake and not both

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No, just the right foot on the throttle and brakes.Just been to the garage and was told it maybe a data prob and that maybe the  gear box needs to be reprogrammed by Toyota😟. Sad! 

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TL;DR: I had similar issues to the original post but with a 2007 Auris MMT. I followed this pdf to initialise the clutch and ECU and it seems to have fixed most of the issues.

http://www.partinfo.co.uk/docs/8734

Hi everyone, this is my first time posting so apologies for any conventions I fail to adhere to or lack of depth of knowledge I may display. I simply want to give back after having gained so much from the simple advice of Devon Aygo. 

I own a 2007 auris 'semi'-automatic (mmt) and have dealt with much the same issues as the original post for months. It started with the car no longer pulling away of its own accord upon releasing the hand brake, unless I applied the accelerator slightly. Then I noticed the jumpiness (kangarooing) at low speeds getting significantly worse. As time progress, gear transitions became less smooth, with a noticeable thud/jolt occuring when entering 2nd or 3rd. Occasionally, the car would judder making a very unpleasant sound when taking off, especially on an incline.

I had no experience with diy mechanics, but decided to change the gearbox Oil as the car had just passed 60,000 miles and it is supposedly recommended at this mileage (it seemed quite clear to me but again, I am not well versed in such matters). This seemed to make the car smoother within each gear, but made no difference to the gear changes (though this may have been a combination of wishful thinking and placebo).

After finding this thread I resigned myself to researching and attempting the ECU and clutch initialisation mentioned towards the top of the thread.

There seems to be almost no information about MMT Aurises whatsoever, with only slightly more available about Yarises and Corrolas. However, I did manage to find this pdf which suggests their systems are almost identical.

The document outlines the procedure for replacing a clutch in an MMT system. Whilst I hadn't had this done, I believed the symptoms indicated the procedure would benefit me. 

My understanding of what the process does is that it resets the actuator and its associate parts and allows it to relearn the appropriate positions at different rev ranges and when to change gear/ apply the clutch and to what degree.

The procedure requires that you create a short between to pins on the OBD2 port, which can seem scary but needn't be. I managed to find a relatively short wire with narrow ferrules (google if necessary) on each end. 

Following the procedure feels uncannily like following an old Playstation 2 cheat code. It involves pressing the brake pedal repeatedly within specific time frames and listening for beeps to sound from the car to confirm the sequences have been entered correctly (try to ensure you do this in a quiet area so you can be sure you're at the right stage by listening to the sounds).

By working through the document (minus the very first procedure, which it states is for preparing the clutch for removal and thus not relevant for our purposes) the ECU should be reinitialised and so should the clutch system. following the latter process and restarting the ignition, it indicates you should hear the gears changing of their own accord. This is quite an unsettling sound but ultimately seems to have had no negative impact on my car.

The final stage is to manually reteach the system when to change gear. This section made me most nervous as I felt I was entirely under the influence of the traffic conditions of the local area and the procedure requires you to use all gears. I decided to postpone this stage till much later at night when I knew the traffic would be minimal, allowing me to focus on changing at the right road speeds. 

The road speeds seem exceptionally high for the relative gears but I decided to stick to it anyway, and you can certainly feel the car struggling a bit at 16mph in first. However, once the gears have been trained and you drive in 'E', the shift occur much sooner in terms of revs than when you changed them manually to train it. I imagine this is because you manually set the max amount of revs and it uses this as a guideline, though I'm not certain.

Bottom line is, it worked. The jolts upon gear shifts appear to have completely disappeared and the car runs much more smoothly than it did before. The jumpiness in first gear at low speeds does seem to have improved but is not gone entirely (this may be a result of me not training it perfectly or just an inherent issue). Furthermore, the car now pulls off of its own accord without the use of the accelerator. I was especially surprised in reverse gear, where the car takes off with quite some oomph.

I hope this information helps someone and thanks to everyone whose contributed to this thread.

Again, this is the pdf containing the procedure I followed.

http://www.partinfo.co.uk/docs/8734

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I used the above document when my old Aygo MMT had jerky changes. 

Transformed the car to as new condition. 

I believe the clutch actuator is always traveling the same short part of 

it's travel. As part of the procedure, it travels its full length before relearning its new position. 

It truly transformed the car. 

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