Odd Acceleration Behavior

[e. prevost94]

Hey guys and gals, my 2015 Soul EV with about 190,000kms (about 100,000 of that I've driven) has always had an odd issue ever since I purchased the vehicle I could never really pin point. Was hoping somebody on here may have experienced the same thing.

The issue happens when I'm accelerating from a stop. I'll give it 1/2 - 3/4 throttle, the vehicle will start to accelerate, but keeps trying to accelerate faster despite not pushing down on the throttle harder. What's even weirder is that if I notice it doing it, I'll start backing off on the throttle but then it starts accelerating even harder until I get down to 20-40% pedal application where it suddenly smartens up and stops accelerating.

I managed to capture live data of the vehicle doing it in the Torque App on my phone, throttle is clearly showing as being commanded at about 50%, but the power going into the EV motor keeps gradually climbing eventually reaching full throttle. The graph matches perfectly what I'm experiencing obviously, I'm wondering if there's maybe a software problem? I have tried re-learning the throttle pedal position with the snap-on scan tool at work, I've also confirmed no DTCs are present. Any suggestions are appreciated

 

[KeeperArtemus]

Yes! I have the same issue on my 2017 +. I notice it when getting on the highway. I drive in 'B' mode on city streets and can replicate the rapid acceleration by throwing the shifter into 'D' as I'm accelerating onto the highway. Acceleration rapidly increases and continues until like you said, I let off the accelerator far more than normal at which point the car goes into a hard regen (two bars on the dash graphic). At that point the car returns to normal operation.

I would like to point out this acceleration is far stronger than the cars usual acceleration. It feels like an increase in torque and power. It's great for getting on the highway, but would love an explanation.

 

[IanL]

Perhaps the car is in "ECO Off" mode? (Button on the centre console two behind the Parking Brake button)
ECO Off is supposed to reset when the car is switched off, but maybe it isn't doing that? Could the button be stuck in?

 

[JejuSoul]

I too guess that this is caused by the "ECO Mode" button. However I'll guess it has been put into "ECO ON" mode. When you are driving with "ECO ON" it will override the normal setting if you push the pedal down hard. As Ian stated the button is on the centre console two behind the Parking Brake button

 

[KeeperArtemus]

I personally never drive with Eco Mode on and can notice right away if it was. This happens in specific circumstances. For me it happens when switching from 'B' to 'D' mode for the first time during a driving session.

As e. provost94 describes, the car will actually continue to hard accelerate as you are letting off the accelerator. It's a weird feeling as if the control of the car is briefly taken away from you.

 

[JejuSoul]

e. prevost94 : here's a graph showing how the car responds to pedal depth.
Repeatedly flooring the accelerator pedal and then letting go a few seconds later.
As far as I know no one has ever analyzed the 'pedal related' PID.
If you have more data or ideas on this please share.

 

[e. prevost94]

Yes! I have the same issue on my 2017 +. I notice it when getting on the highway. I drive in 'B' mode on city streets and can replicate the rapid acceleration by throwing the shifter into 'D' as I'm accelerating onto the highway. Acceleration rapidly increases and continues until like you said, I let off the accelerator far more than normal at which point the car goes into a hard regen (two bars on the dash graphic). At that point the car returns to normal operation.

I would like to point out this acceleration is far stronger than the cars usual acceleration. It feels like an increase in torque and power. It's great for getting on the highway, but would love an explanation.

Thanks for the reply! Yes that's exactly the problem, I did forget to mention the increased power but yeah same thing. Have you owned the vehicle since new? If so when did you first notice it doing it? If not, did it do it from when you bought it used, or did it come later? I'm trying to figure out if this was something that the car did since new or if developed after it was new but before I bought it. Thanks again

 

[e. prevost94]

Perhaps the car is in "ECO Off" mode? (Button on the centre console two behind the Parking Brake button)
ECO Off is supposed to reset when the car is switched off, but maybe it isn't doing that? Could the button be stuck in?

The button does work, but this is not related. It's almost in a way like it's doing the opposite. I forgot to mention it in the original post, but the other commenter reminded me that the vehicle seems to accelerate faster than normal, like it has extra power than max

 

[e. prevost94]

I too guess that this is caused by the "ECO Mode" button. However I'll guess it has been put into "ECO ON" mode. When you are driving with "ECO ON" it will override the normal setting if you push the pedal down hard. As Ian stated the button is on the centre console two behind the Parking Brake button

Thank you, good suggestion but this is unrelated

 

[e. prevost94]

e. prevost94 : here's a graph showing how the car responds to pedal depth.
Repeatedly flooring the accelerator pedal and then letting go a few seconds later.
As far as I know no one has ever analyzed the 'pedal related' PID.
If you have more data or ideas on this please share.

View attachment 40

Thank you for the graph, I'll do some more data logging and see if I can get it to act up again that helps. I'll try and increase the time graph time, should I get the same data as before? Also I'm not too sure what pedal related is, I try and grab as much info even if I don't fully understand what it's really for just in case it's relevant. I'll disregard that data pid on my next test

 

[KeeperArtemus]

Thanks for the reply! Yes that's exactly the problem, I did forget to mention the increased power but yeah same thing. Have you owned the vehicle since new? If so when did you first notice it doing it? If not, did it do it from when you bought it used, or did it come later? I'm trying to figure out if this was something that the car did since new or if developed after it was new but before I bought it. Thanks again

I purchased my 2017 + used in 2019. Second owner. In 2020 I had the battery replaced under warranty due to massive degradation. I want to say the issue began after the battery replacement. It wasn't occurring when I first bought the car. It is currently back at Kia post BMS recall awaiting a battery or I could provide more info.

I purchased a 2019 + just this month. (I just couldn't stay away for that long.) I'm the second owner and it has 19,400 miles on the odometer. From service records I do believe I have the original battery. I've tried to replicate the issue a few times with no success. I'll keep trying!

 

[e. prevost94]

I purchased my 2017 + used in 2019. Second owner. In 2020 I had the battery replaced under warranty due to massive degradation. I want to say the issue began after the battery replacement. It wasn't occurring when I first bought the car. It is currently back at Kia post BMS recall awaiting a battery or I could provide more info.

I purchased a 2019 + just this month. (I just couldn't stay away for that long.) I'm the second owner and it has 19,400 miles on the odometer. From service records I do believe I have the original battery. I've tried to replicate the issue a few times with no success. I'll keep trying!

Thank you, this is good info. Come to think of it, I also had my high voltage battery replaced under warranty basically right after I bought the car. I'm wondering if it also started around the same time and I didn't notice. I bought the car a little over 4 years ago and the battery was replaced like 3 weeks after so my memory is a little fuzzy

 

[e. prevost94]

I purchased my 2017 + used in 2019. Second owner. In 2020 I had the battery replaced under warranty due to massive degradation. I want to say the issue began after the battery replacement. It wasn't occurring when I first bought the car. It is currently back at Kia post BMS recall awaiting a battery or I could provide more info.

I purchased a 2019 + just this month. (I just couldn't stay away for that long.) I'm the second owner and it has 19,400 miles on the odometer. From service records I do believe I have the original battery. I've tried to replicate the issue a few times with no success. I'll keep trying!

This is a long shot, but you don't happen to still have the receipt from when your pack was replaced? Due to us coincidentally getting our packs replaced around the same time, and us also having the same concern, I'm curious if we have the same part number for our replacement pack and maybe that's connected somehow. Also, I see on my receipt that the tech did a "BMS logic improvement", maybe because they're doing a bunch of them both of our techs accidently forgot to do that and simply mis-remembered and this concern is the result of not doing the improvement? Maybe I'm grasping at straws tho, idk

 

[FLKiaEV]

I have a 2018 and previously had a 2016 Kia Soul EV, but never noticed this behavior in either one. I always keep it in Eco Mode and 'B' (unless I'm driving on the highway for an extended period of time, then I'll switch to 'D' mode). If you feel it is potentially dangerous I would definitely have the dealer examine it.

 

[e. prevost94]

I have a 2018 and previously had a 2016 Kia Soul EV, but never noticed this behavior in either one. I always keep it in Eco Mode and 'B' (unless I'm driving on the highway for an extended period of time, then I'll switch to 'D' mode). If you feel it is potentially dangerous I would definitely have the dealer examine it.

Oddly enough, it doesn't do it in Eco mode. While I don't think it's dangerous as the it stops once throttle is released, I did make a service appointment. I'll report back after my appointment next month

 

[KeeperArtemus]

This is a long shot, but you don't happen to still have the receipt from when your pack was replaced? Due to us coincidentally getting our packs replaced around the same time, and us also having the same concern, I'm curious if we have the same part number for our replacement pack and maybe that's connected somehow. Also, I see on my receipt that the tech did a "BMS logic improvement", maybe because they're doing a bunch of them both of our techs accidently forgot to do that and simply mis-remembered and this concern is the result of not doing the improvement? Maybe I'm grasping at straws tho, idk

Pulled all my service records.

09 SEP 2020 - Battery SOH confirmed at 54%. BMS Logic update performed. SOH now reads 100%.
29 SEP 2020 - Battery SOH confirmed at 36%. HV Battery pack approved for replacement.

Here is what is written on the invoice:

Diag Diag
79671 WPK
1 37510-E4200R REMAN PACK ASSY-BATT
CORE CHARGE W
1 37513-E4000 BATTERY MANAGEMENT S
-1 37510-E4200R CORE RETURN

 

[e. prevost94]

Yes! I have the same issue on my 2017 +. I notice it when getting on the highway. I drive in 'B' mode on city streets and can replicate the rapid acceleration by throwing the shifter into 'D' as I'm accelerating onto the highway. Acceleration rapidly increases and continues until like you said, I let off the accelerator far more than normal at which point the car goes into a hard regen (two bars on the dash graphic). At that point the car returns to normal operation.

I would like to point out this acceleration is far stronger than the cars usual acceleration. It feels like an increase in torque and power. It's great for getting on the highway, but would love an explanation.

So I dropped my Soul off at the dealer on Saturday and just picked it up today. They were able to replicate the issue and called for replacement of the accelerator pedal assembly which I approved. Seems to be good now, would have done it at least once on my drive home so I think we've found our concern! Total cost to diag and fix was about $725 Canadian, but knowing what the problem is now it would be about $400 for the part and install if they're willing to skip diag for ya

 

[e. prevost94]

e. prevost94 : here's a graph showing how the car responds to pedal depth.
Repeatedly flooring the accelerator pedal and then letting go a few seconds later.
As far as I know no one has ever analyzed the 'pedal related' PID.
If you have more data or ideas on this please share.

View attachment 40

It turned out to be the APS. Took it to the dealer and they were able to catch one of the position sensors reading 85% when at half throttle, I guess Torque must only provide data on one of the sensors or processes the information differently than the factory scan tool. Either way, it seems to be fixed now

 

[JejuSoul]

Congrats on finding a fix for this. And thanks for posting the info about sensor data.
The part cost is much less than $400.

 

[e. prevost94]

Congrats on finding a fix for this. And thanks for posting the info about sensor data.
The part cost is much less than $400.

View attachment 68

Good to know the part is available for cheap! I considered going that route, but wanted to have the tech verify the repair just in case he was wrong and needed to continue with diag and also save me a return trip to the dealer. Now that there's a confirmed fix, next person with the same problem can save their money