2015 Mitsubishi Mirage 1.2L RF CVT Issues

[Mathew_Boss]

I have a 2015 Mitsubishi Mirage with a little over 89kiles on it. The transmission has been acting up for about 15k miles. I took it to Certified Transmission and they said the transmission was fine but the engine was under powered. It's a 74hp 3 cylinder of course it is under powered. Anyway, if you were driving with cruise control on it would just randomly rev to the rev limiter and you would have to cancel and resume cruise and it would work again. Once it started doing it consistently l, if I changed the CVT fluid that would fix it for a few thousand miles before it started up again. The fuel economy also went from 50mpgs to under 30mpgs on average (I commute 90 miles a day)

About 3 weeks ago it finally had a no start and check engine light and it was the day before we left for a funeral cross country.

After posing on a mirage owners group they said it was probably just the speed sensors. I bought 2 sensors from Amazon and switched them out yesterday. Now the car starts (before it was acting like it was stuck in gear) Park, Neutral and reverse work but when I put it in drive it acts like it's stuck in low gear. When you change it to low there is no change to the behavior of the transmission.

The sensors I bought were super cheap from Amazon so my wife and I talked about buying name brand ones to try. Anyone who has input I would greatly appreciate the feedback.

 

[JavierH19]

I don't think there's anything actually wrong with the trans it seems like an odd electrical/computer misunderstanding. But when this car was having these issues 15k miles ago were you not able to take it to the dealer? These have a 10y 100k powertrain warranty which it likely still has today unless you bought it used as that warranty is only for the first owner. If you are the first owner why didn't you take it in? Check your warranty coverage if you're unsure and if you are still covered put the old stuff back on it. The dealer won't like that aftermarket stuff you put on and will deny warranty.

The mpg going down a lot means it's not applying the correct ratio to the pulleys. I would see if i can get the trans programing cleared and there could be something that has a low voltage as that an cause similar issues in other transmissions. I wonder if one of the seals inside is letting trans fluid in and causing resistance. I'd look into pulling the pan and checking the valve body.

 

[supton]

Have you asked on the Mirage forum? I think the fummins guy was here not that long ago, but I don’t recall what his user name is on this forum. He seems to have good luck with these cvt’s.

 

[KGMtech]

I've heard so much bad about buying automotive sensors, critical parts from Amazon that I stopped. Too many fakes.

 

[atikovi]

Isn't that a Jatco CVT like the ones in Nissan Versas that go bad at 80-100K? You need a scan tool to read live data and see what the sensor is reporting to the computer. While the cheap Amazon sensor might be junk, the transmission might be slipping too, hence the code.

 

[JTK]

I'd start with simple stuff like make sure your battery and charging system is 100%. Low system voltage can cause the CVT to act stranger than they already are.

Then scan for codes and check some live data in the areas of concern. Loose the aftermarket sensors ASAP for OEM parts. The aftermarkets are most likely not reporting correctly.

Normally if a CVT is chewing itself up, it ain't gonna go for another 15K miles.

 

[Mathew_Boss]

I don't think there's anything actually wrong with the trans it seems like an odd electrical/computer misunderstanding. But when this car was having these issues 15k miles ago were you not able to take it to the dealer? These have a 10y 100k powertrain warranty which it likely still has today unless you bought it used as that warranty is only for the first owner. If you are the first owner why didn't you take it in? Check your warranty coverage if you're unsure and if you are still covered put the old stuff back on it. The dealer won't like that aftermarket stuff you put on and will deny warranty.

The mpg going down a lot means it's not applying the correct ratio to the pulleys. I would see if i can get the trans programing cleared and there could be something that has a low voltage as that an cause similar issues in other transmissions. I wonder if one of the seals inside is letting trans fluid in and causing resistance. I'd look into pulling the pan and checking the valve body.

I bought it used. It was a repo car with 69k miles on it when I bought it. No warranty available. I ordered name brand sensors. 2 pulley sensors and the speed sensor I'll just do all 3 that way they are all new and the same brand.

 

[Mathew_Boss]

I'd start with simple stuff like make sure your battery and charging system is 100%. Low system voltage can cause the CVT to act stranger than they already are.

Then scan for codes and check some live data in the areas of concern. Loose the aftermarket sensors ASAP for OEM parts. The aftermarkets are most likely not reporting correctly.

Normally if a CVT is chewing itself up, it ain't gonna go for another 15K miles.

I just replaced the battery this winter I had a brand new interstate battery that's not even 6 months old. It starts strong and quick. At least until this issue showed up.

 

[Mathew_Boss]

UPDATE: I have reincarnated her. I swapped out 3 out of the 4 transmission sensors with Beck/Arnley sensors and she works again. At least one my 8 mile test drive. I'll be driving it 90 miles to work and back tomorrow. I'll report back on if the MPGs improved back to normal or if they are still terrible.

 

[zzyzzx]

Last time I had a transmission sensor code like that I bought a new Rostra branded sensor and that fixed it good.