[OurAscent]

Hello, everyone.
We're the original owners of a 2020 Ascent, which hasn't had any warranty or reliability issues until today. We got the transmission recall inspection/servicing done 2 weeks ago at the dealership, they told us that a boroscope inspection showed all's well, and they updated the transmission firmware. About 1000 km of driving later, the car started having problems.

While idling in a parking spot, my wife reported hearing a "popcorn noise" from under the hood. The sound has not occurred since. Shortly after we started driving it, from a speed of about 40 km/h (25 mph) the car started to slow down, while engine revs showed about 2000. I pressed down on the accelerator, it had no effect. After 5-10 seconds of this behaviour, the engine's rpms went up, and the car started to accelerate with a jerk. This happened 4 more times over the next 10 minutes of driving, with the rpms indicating between 1000 and 2500 on each occasion.

We were not using cruise control, and neither eyesight nor traction control showed any indication of being involved. The roads were empty of other vehicles, and while there was snow around, the roads weren't slippery at all.

A second problem started to occur at the same time: the car icon that appears in the middle of the instrument panel showed the brakes as being applied when my foot wasn't on the brake pedal. The lights would sometimes flicker off and on over a span of seconds, other times the brake lights would be on continuously over 5 seconds. During these times, the car drove as though no brakes were being applied.

Has anybody seen this issue before? And, can anyone reccommend a good Subaru troubleshooter near Ottawa, ON?

Any advice would be useful at this point: Getting time at a dealership/subaru mechanic is going to be tough, and we've got a long way to drive to get there..

 

[OurAscent]

This is something I strongly suggest you take to a dealership - this is not something I'd take to a non-dealership "troubleshooter".

The throttle and brakes are not just two different systems, but one is "drive by wire" (throttle), while the other is mechanical (brakes).

To be clear: the brakes are only being applied when I press the brake pedal, it's the brake light indication on the car icon on the instrument panel that's acting odd.

 

[OurAscent]

Sorry, to be clear, that light is driven by the status/position the computer thinks the brake pedal is in. That's a very important data point to be wrong.

Do you two foot drive?

If not, I'd take it in - to a Subaru dealership.

I do not two foot drive. I wondered if a door mat was rubbing against the pedals (in our snowy climes, door mats can get in the way), but the doormat was properly secured, and wasn't touching the pedals...

Thank you very much for your ideas. They're very helpful.

 

[OurAscent]

Thanks for the ideas, Robert.Mauro & Packard8. I spoke with my dealership, and with a local independent Subaru Mechanic. The independent mechanic is critical of the recall, he thinks that a boroscope inspection of the transmission is useless, he feels the only conclusive test for transmission damage is to drain the transmission fluid & inspect it for metal.

Both mechanic and dealership suspect my transmission is self destructing, and the dealer's asked that my car be towed, not driven, in for servicing. "It might take some time, we're getting a lot of transmission replacements these days". Gulp. The car is 2 yrs, 5 mos old, & has 74000 km.

 

[OurAscent]

Our Subaru dealer: Ogilvie Subaru says there's no need to look at the transmission. They found a faulty brake light switch, so the troubleshooting stopped there. They say it's a non-warranty repair, I'm just worried that after we wait 3 days to get the new switch put in we'll still have a transmission problem.