Loss of power after hitting the brakes hard

[jamie885]

Hey guys

I have a MY11 VRX CVT today I had to slam the brakes on, when I went to accelerate off again I had my foot almost flat the car was reving but barely moving.

After 30 seconds it went back to normal.

Is this normal with the CVT or is something wrong?

[debonaire]

So it was revving unrestricted, the engine under load but you were being held back as if the handbrake was on?

[Dire]

Idk anything about CVTs but was it in manual mode in a high gear?

[jamie885]

So it was revving unrestricted, the engine under load but you were being held back as if the handbrake was on?

Pretty much yeah there was a bit of movement but not alot.

[aspir3]

It sounds like the ASC kicked in. You can often tell by the car skidding sign on the dash.

The ASC stops the throttle body from opening even though you foot is down on the accelerator. This is a safety factor of our cars.

If in doubt take it to you Mitsubishi dealer.

[SAM-24A]

That doesn't sound normal for a CVT or other Transmission for this matter.

It's a bit difficult to decipher when we don't know the entire circumstance and/or conditions during this occurrence.
Many factors such as the Road Surface, Speed, Duration & Length of Braking etc could influence this.

This sudden braking (quote= "slam the brakes on") would have engaged the ABS & ASC features and may have also disengaged the CVT drive as part of the integrated safety features programmed within it's ECU.

The best explanation I can offer is that perhaps your application of "full" acceleration immediately following the sudden braking event resulted a conflict message to the CVT ECU.

The CVT probably went into a "safe mode" until such time as you eased-up on the accelerator .... and allowed the ABS / ASC & the CVT ECU to work out that everything was OK and allowed Drive Engagement.

30 seconds Revving an engine and not going anywhere is a long time .... lol .... not to mention the road rage from stalled traffic behind you.
Perhaps it felt like 30 secs because you felt helpless to understand WTF was going on.


Sam .....
Merlinised MIVEC - AspiRe 2.4L
Merlin Inspired Variable Engine Control

[jamie885]

I was doing about 30km/h and the ASC/ABS etc didnt engage is wasn't that hard of a brake.

I tried it again and it did the same thing though not as bad.

The car does move but just slowly.

I'll see if i can get a video of it.

[debonaire]

It sounds like the ASC kicked in. You can often tell by the car skidding sign on the dash. The ASC stops the throttle body from opening even though you foot is down on the accelerator. This is a safety factor of our cars. If in doubt take it to you Mitsubishi dealer.

That's what I was thinking at first but would've thought that ASC would actually stop the engine from revving, but he says the engine responded normally and he just didn't go anywhere.

[Slash]

Sounds like the transmission went into protection mode and limited throttle

[bryzabone]

Guys, this is normal. The CVT will disengage itself in a sudden stop event, i.e. abs engagement.
The CVT is disengaged, the car does its thing, its brain helps you control, and stop the car.
When you want to drive away again, the cvt is re-engaged, but its been disconnected- hence, now its in "3rd" gear. A cvt must move forward, like a bike chain gear, to change ratio is the best analogy.
the revving is like if you were riding a clutch in 3rd to take off from a start. not having a clutch, the revving hard is to make the engine provide the power and torque for the current ratio in the cvt to work.

I came across this the hard way, in several driving and advanced car control courses. the trick is to learn how to threshold brake just enough, and viola, you can power out of a hard-swerve manoeuvre easily

P.S. - sports mode will not matter, the cvt will behave the same way....

[chunky9]

Great info Bryan!

[Cammo00]

it sounds like the cvt gearbox isn't shifting down the gears after slowing down very quickly. can be caused by a lot of things? loss connection , TPS, ECU, corrosion, Etc. sorry mate cant help you there. take it to a Mitsubishi dealer maybe. good luck

[bryzabone]

it sounds like the cvt gearbox isnt shifting down the gears after slowing down very quickly. can be caused by a lot of things? loss connection , TPS, ECU, corrosion, Etc. sorry mate cant help you there. take it to a Mitsubishi dealer maybe. good luck

chris, this is normal behaviour. its not caused by corrosion, loose connections, its a safety mechanism built in, to stop destoying the steel belt in the cvt.