Cvt problem?

[kladdis]

Hello.

I was just wondering if anyone know why my Qashqai -16 1.2L petrol is behaving like this? Mostly when on Cruise control. Its an automatic. 50 000km on the clock. (31000 Miles)



I took it to the Nissan dealer and they said that they couldn’f find anything thru the OBD2-port.
When its dropping ~200 rpm the entire car shakes.
If I manually put the 7th gear in, it doesn’t drop.
Sorry for the bad english.

Best regards.

[gloucester]

Welcome to this forum.

Let's hope someone will be around soon with CVT experience.

[Qashowner]

That is how they work, in a CVT box you only really have one gear and the cones operate to make that gear higher or lower ratio. When you engage cruise control, the engine is trying to run as efficiently as possible and any slight deviations in the road surface will raise and lower you rpm. It becomes more noticeable AFAIK on lower BHP cars as the engine needs to work a little harder to maintain the speed, which is what the cruise control is trying to do.

[kladdis]

That is how they work, in a CVT box you only really have one gear and the cones operate to make that gear higher or lower ratio. When you engage cruise control, the engine is trying to run as efficiently as possible and any slight deviations in the road surface will raise and lower you rpm. It becomes more noticeable AFAIK on lower BHP cars as the engine needs to work a little harder to maintain the speed, which is what the cruise control is trying to do.

Thanks for the reply but I don’t think this is normal since the RPM drops 200 rpm, and then jerks, and goes up to 2200(or whatever it was at before the drop)

If I drive 25 km, grab a meal (I mean wait 15-30 min) it runsten perfect. The jerking started 3 months ago, maybe 1 time during 10 drives. Now it does it 98 out of 100.

Since I’ve got 2 kids, and winter is coming up here in Sweden (-25C) I don’t want the car to break down. I consider leaving it to the local dealer, but it’s 70km from my town, and I dont feel to pay lots of money for them to guess what it is.

My guesses is at the Air flow meter, or something like that.

[calnorth]

If the dealer missed that erratic performance then there is something wrong with the dealer. The diagnostics for engine control as regards cruise control or as Nissan call it AUTOMATIC SPEED CONTROL DEVICE (ASCD) is large. It requires Nissans Consult test and diagnostics tool to determine what the fault is.

We do not have accurate technical details of engines or gear boxes (CVT) to determine the problem.

ASCD uses various sensors to signal the ECU to control fuel and timing etc. The rev fluctuation/juddering could be symptomatic of the ECU or its actuators failing to fuel the engine...a kind of stalling. You also seem to experience a temperature dependency which could be significant?

You need to speak to a dealer technician who understands this problem...not a booking in clerk. Sorry to be unhelpful.

[kladdis]

If the dealer missed that erratic performance then there is something wrong with the dealer. The diagnostics for engine control as regards cruise control or as Nissan call it AUTOMATIC SPEED CONTROL DEVICE (ASCD) is large. It requires Nissans Consult test and diagnostics tool to determine what the fault is.

We do not have accurate technical details of engines or gear boxes (CVT) to determine the problem.

ASCD uses various sensors to signal the ECU to control fuel and timing etc. The rev fluctuation/juddering could be symptomatic of the ECU or its actuators failing to fuel the engine...a kind of stalling. You also seem to experience a temperature dependency which could be significant?

You need to speak to a dealer technician who understands this problem...not a booking in clerk. Sorry to be unhelpful.

Thank you for your reply. I was mostly scared that it would be the gearbox that’s breaking down. I’ll give the local dealer a ring, and book a full check of my car. Hopefully if it’s a major error my Nissan insursance company Will help, or maybe goodwill from the garage. Thanks again.

[calnorth]

ok..we are guessing really and due to lack of technical info. So let us know what happens please

[kladdis]

I took my car to the dealer today. They suspected the gearbox slipping. They were gonna make a call to Nissan, for trying to get fixed on extended warranty. If that didn’t work they were going to try on my insursance.