MPG 4MPG lower after Software upgrade/Recall

welcome!

yes, quite a few. unfortunately, there doesn't seem to be a fix. you might request a do over, in case they botched it, but i don't recall that fixing it for anyone.

 

The software update you mentioned Is to fix the non limp mode. Sounds like an accumulative upgrade which consist of previous software upgrades was part of it also; the one that reduces inverter uptime and more gas time.

There’s a PC member here that has recall documents piled up &yet to be completed, I have the same pile also.

 

<raised hand emoji>

 

So do you suggest telling the dealer NOT to do the upgrade, if the car is there for some other work?

I wonder whether they can follow that instruction or are required to do the upgrade -- i.e. would refuse to work on the car if permission for the upgrade is declined.

 

I'm sure everything is reset like when battery is disconnected so may take a tank to improve.

Posted via the PriusChat mobile app.

 

Prius engine management system has to relearn?? As @audiodave has already mentioned, give it a few tanks. Keep us posted.

 

Once battery is disconnected there is some adjusting the computer needs to do. That's on all computer controlled cars.

Posted via the PriusChat mobile app.

 

i refused the gas pedal haircut and floor mat zip ties, they just note it in your records in case the car kills you.

 

Would you please describe the non limp mode? What fix is needed?
Last week ( about 1000 miles ago). dealer changed HV battery in my car and did s/w upgrade. I was sure my mpg will go higher but instead lower .now city avg is 40mpg and fwy is abuut 47. My tires are on 40psi

 

I doubt a battery disconnect is gonna throw off the car's mpg. I purposefully disconnect when doing brake work, and the only odd thing I notice is a distinct rev-up, at the next 2 or 3 start ups, like it's recalibrating throttle response or something.

I would contact the service manager regarding that fiasco. Also, it could be a factor in your mpg drop. And 90 miles post service visit is not much: per other responders, give it at least a full tank, might just be short trips.

There have been mpg issues with that, back when the first inverter software update was being applied.

 

If some brave souls who are going to have the recall applied (I think I will, just waiting for dealer to get the hang of it first) can use Techstream and note down their current calibration IDs before going in for the update, as described over here, we'll have more and better information.

 

this could be easily your answer. prius' MPG reacts to tire rolling resistance out of proportions. i noticed that when i went from stock tires to less LRR tires.

 

Dealer will lower the tire pressure to door placard lbs. Plus they leave the doors open the whole time they work on the car so the 12 volt battery gets hammered.

Every time my car has been at the dealer it gets terrible mileage for quite a while.Like audio dave says it takes a while to get it aback to where it was.

 

They have your battery on a 12 volt shop supply the whole time so it can't get hammered in the middle of reflashing an ECU. Nobody wants to brick the car....

 

YES! I had the exact same issue and question. I lost about 5 mpg after the update. I'd really like to know what the update did.

 

Did you retrieve and save the old calibration version numbers from your HV ECU before taking the car in for the recall?

If not, you'll never know....

 

No, you are not required to take the update. They will ask if you want but you can decline with no issue.

 

I'm really surprised you guys refuse all these updates and recalls. Be careful out there.

 

As of present, the manufacturer is obligated to notify the owner of a recall but the owner is not obligated to have the recall performed. Simply tell your dealer service writer yay or nay on the recall. She will still gladly take your money for whatever non-recall work you want done.

Survey: Not Everyone Wants to Require Owners to Get Recalled Cars Fixed