Strange behavior of the hybrid system

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MatsAstrom

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XC90 T8 2018 Inscription

Joined Sep 16, 2022

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5 Posts

Discussion starter · #1 · Sep 16, 2022

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My XC90 T8 2018 has started to behave strange lately. It has approx 108000 kilometers on the meter. Previously no problem with the hybrid system. As long as the battery have some charge in it it worked flawlessly. Now it starts the petrol engine intermittently, very often when I’m braking. For example if you drive on the highway in electric mode and pull over at for ex a gas station it often starts the combustion engine. Also when I drive to my own property I have a slight slope and then a turn right at my house, almost always when I brake after the slope and make the right turn the petrol engine almost always starts. Have not behaved like this before. Had it for service and gets the traditional answer “no fault codes” and a bill for approx $100.

Have anybody else had this problem?

Regards,
Mats

 

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dgomes

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2022 XC90 T8 Inscription, 2018 XC40 T5 R-Design, 2017 XC90 T6 Inscription

Joined Apr 13, 2021

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463 Posts

#2 · Sep 16, 2022

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I had not experienced or have heard of that specific problem, but there seems to have been several software upgrades related to engine and transmission and, if this is/was a sw issue it is possible that it may be corrected.

Do you know if they did a Total Software Upgrade when you brought the car in?

If not, I would start there.

 

DFrantz

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Joined May 14, 2018

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10,656 Posts

#3 · Sep 16, 2022

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Could it possible be related to traction at the given area? Slippage detected could be engaging the awd, which uses the gas motor. Maybe there is more tire wear than before, or maybe there is more gravel on the road? Breaking more aggressively? Just guesses.

 

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MatsAstrom

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XC90 T8 2018 Inscription

Joined Sep 16, 2022

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5 Posts

Discussion starter · #4 · Sep 17, 2022

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The dealer didn’t do any software updates, bill says just “Fault finding”, “No fault code found”.
Have regular service next week, maybe they perform an update then.
Does starting the ICE depends on if car isn’t horizontal, the ICE starts as I wrote when going uphill, without needing to engage the gas pedal a lot. Also when braking the car is probably “kneeing” a bit, even if braking isn’t that forceful. Can it be some “oversensing” of a “gyro function”?
Have noticed that when loosing traction, then the ICE starts, but tire wear? Will that really differ so much that the car thinks I’m sliding?

Thanks for all input👍

 

DFrantz

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#5 · Sep 17, 2022

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It's not about the car thinking your sliding... it's with worn tires you will slide more. You shouldn't need to detect slippage before the AWD kicks on, the cars slip detection is far better than our own. That's where I was going with the tire wear.

Uphill will need more power, and with the older T8 system it didn't always take a whole lot of asking for power for it to switch the gas on... however, that wouldn't change over time so much, so unless it feels it's slipping going uphill, which again, could be from tire wear, I don't suspect the actual angle of approach itself is a direct factor, but could cause other conditions that are.