Jerky CVT at Low Speed - Torque Converter Lock Up Clutch?

[mattl369]

Evening All,

I recently purchased a 2013 Jazz EX CVT, now with 6,000 miles on the clock, though there's something that's bothering me and I wonder if anyone else has experienced this.

When coming to a stop, whilst braking, at approximately 9 mph there is, what I can only describe as a soft 'jolt' before the car comes to a stop. I can only liken it to driving a manual car, in gear, not pressing the clutch - you get to the speed where the car is going to stall and you then react and press the clutch down.

This jolt is much more pronounced when you release the accelerator, but coast to a stop without using the brake. The gearbox tries to provide some engine breaking and again at 9ish mph there is a pronounced jolt.

My expertise is not in automotive engineering, however it feels as though the lock up clutch for the torque converter is not releasing early enough and it gets to a point when it 'emergency' releases and causes this jolt. This can somewhat be prevented by pressing the + steering wheel paddle at about 15 - 20 mph. Any less than that and, again, you can feel a jolt when you press it. A quick prod on the accelerator at this kind of speed also seems to release the lock up clutch and prevents this jolt.

Also at lower speeds, it's obvious the lock up clutch is still active - e.g. slowing down and turning into a side street. This can cause 'jerkyness.' Traffic is especially bad. Though this can be avoided by putting it into S mode - obviously the lock up clutch doesn't operate at lower speeds in this instance. It also doesn't happen when the car is cold.

Sorry for the long winded post, but just wanted to see if this is 'normal' or I need to take it back to Honda.

Thanks! Matt

[Pine]

I noticed this on my CVT, and it has been mentioned on this forum before. The effect is more evident on some cars than others with some owners not noticing it at all. I had it slightly on my Mk1 Jazz and found it more pronounced on my Mk2 making it difficult to come to a halt smoothly. Although the CVT is great when on the move I bought another make when I changed my car and now coming to a smooth halt is a pleasure.

If you are not happy with it I should take it to a dealer, let them have a drive and see what they say.

[madasafish]

Evening All,

I recently purchased a 2013 Jazz EX CVT, now with 6,000 miles on the clock, though there's something that's bothering me and I wonder if anyone else has experienced this.

When coming to a stop, whilst braking, at approximately 9 mph there is, what I can only describe as a soft 'jolt' before the car comes to a stop. I can only liken it to driving a manual car, in gear, not pressing the clutch - you get to the speed where the car is going to stall and you then react and press the clutch down.

This jolt is much more pronounced when you release the accelerator, but coast to a stop without using the brake. The gearbox tries to provide some engine breaking and again at 9ish mph there is a pronounced jolt.

My expertise is not in automotive engineering, however it feels as though the lock up clutch for the torque converter is not releasing early enough and it gets to a point when it 'emergency' releases and causes this jolt. This can somewhat be prevented by pressing the + steering wheel paddle at about 15 - 20 mph. Any less than that and, again, you can feel a jolt when you press it. A quick prod on the accelerator at this kind of speed also seems to release the lock up clutch and prevents this jolt.
ed post, but just wanted to see if this is 'normal' or I need to take it back to Honda.

Thanks! Matt

The CVT automatically changes into 1st gear..  Hence the jolt - as the engine speed is too low..

Happens on mine as well.

[nab]

The CVT does not have gears its a CVT !!

[VicW]

I don't think that a CVT has a torque converter either, it has a starter clutch.

Maybe I have been lucky but I have had three CVT's and none have or have had this problem.

Vic.

[mattl369]

Pine - thanks for confirming. I've looked everywhere, but could only find stuff on the gen 1 juddering issue.

madasafish - there are no gears, it's a belt between two 'rollers' that vary in size to create different ratios, but either way, sounds like you are experiencing the same issue.

VicW - I believe it was only the first gen that had a starter clutch which, from what I can gather, was its only weakness! For the second (and third) gen, they use a torque converter which 'locks up' very early.

Anyway, I've spoken to Honda about it and booked in for Tuesday. When I tried to explain the issue, the person thought I was talking about it juddering, but have written a thorough e-mail explaining everything. Hopefully there will be a fix of some kind. 

It may just be me, but it seems to have gotten worse over the last couple of months.

[Pine]

Have a look at this thread, at the time I think I still had my Mk 1 Jazz:

2012 CVT transmission problem

[Kenneve]

Hi Guys

As I understand it, the Mk1 CVT Jazz has a starter clutch, not unlike a manual gearbox, but electronically operated.
The Mk2 & Mk3 CVT Jazz has a normal torque converter similar to most automatic cars.
I have had 3 Jazz cars, a Mk1 and 2 Mk2 models. The current car is a 2013 model and definitely has a Torque Converter.

If I slow down without using the brakes, then there is certain amount of engine braking from maybe 12MPH down to about 3MPH, at which point, braking effect stops and the car continues to move forward at tickover speed.
It is possible to feel the change of effect, but there is no jolt.
I find this feature very useful in long lines of traffic, when one able to creep forward as necessary.

As other members have said, if you are happy, then get your dealer to check it out.

Regards Ken.

[VicW]

VicW - I believe it was only the first gen that had a starter clutch which, from what I can gather, was its only weakness! For the second (and third) gen, they use a torque converter which 'locks up' very early.

As I understand it, the Mk1 CVT Jazz has a starter clutch, not unlike a manual gearbox, but electronically operated.
The Mk2 & Mk3 CVT Jazz has a normal torque converter similar to most automatic cars.
I have had 3 Jazz cars, a Mk1 and 2 Mk2 models. The current car is a 2013 model and definitely has a Torque Converter.

Thanks for that folks. I now know why my current 2011 CVT feels slightly different to and better than my earlier 2006 cars.

Vic.

[madasafish]

The CVT does not have gears its a CVT !!

Err it has 7 fixed speeds.. so it changes its choice of speed - eg gearing..

[guest1372]

Err it has 7 fixed speeds.. so it changes its choice of speed - eg gearing..

You are right in that you can choose from 7 ratios, but that is just one of the modes that simulates gears from positions of the Continuously Variable Transmission belt.

The joy of the CVT is its ability to maintain engine revs at the optimum for the load required in a smooth band with no steps.
--
TG


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[edam]

From reading this post you could believe that Honda make 2 different CVT gearboxes

Going back to the original question

I have not noticed judder when I brake hard to a stop.
I have not noticed judder when I coast to a stop although I do notice when the engine braking stops.
But I have noticed judder when I lightly brake to a stop.

[mattl369]

Well, after putting it off for a week, I booked the car in to my local dealer to have a look at. I also emailed them with full details of the issue.

They carried out a software update to the CVT and a road test apparently confirmed all was well. Well, the upshot is that the issue I had is still there, although on the way home this evening it didn't seem as pronounced as it was. However, there is a huge improvement when driving in traffic. Previously I resorted to putting it into S mode as it was so jerky, but I didn't need to do this today.

Not sure of my next move - may possibly email Honda UK if I've the inclination!

[guest5355]

Hi. We had a problem similar to yours but not as bad,  we found out that an error was made on the vehicles 2nd service, they did not change the CVT fluid as per the new servicing information. We purchased our Jazz, 1.3 EX CVT in March 2015, it was a ex Motability vehicle with 15K miles on the clock.
 After 4 or 5 (105 mile round journeys) visits to the Honda dealer that we purchased it from in Kent (not the original dealer) to try and sort the problem out with no luck. my Wife searched the internet and she found an article from someone in Italy, who had the same problem and the solution was a last found, drain the CVT fluid and have the box flushed and refilled  with Honda fluids, we have not had any problems with the CVT since. This is what can happen when the CVT fluid is not change every 2 years on this model
 I must add that all of the costs were picked up by the Honda dealer that we purchased the car from

[VicW]

There appears to be a difference in the recommended CVT gearbox fluid change interval.
My 2011 model handbook says every 75K miles or six years.
My Honda dealer says Honda are now saying change at 25K miles or two years which I believe was the change interval for the earlier CVT's which I have I had and was when I had the fluid changed and will continue to do so.

Vic.