Limping start and power collapse on hill

[John Hof]

Recently my 2016 Prius limped into motion from a standing start and continued doing this at every traffic light and round about until home. The next day it appeared to have corrected itself. There were no warning lights.

Two days later it could barely climb up a steep hill. No warning lights

I have had the car thoroughly checked out but nothing was found.Has anyone noticed anything similar as I have lost confidence in the car as there is no explanation.

[Gerg]

Is the car a gen3 (->2016) or a gen4 (2016 ->)?

How many miles/kilometres has the car done?

Was the car checked over at an independent service agent or a Toyota dealer?

Does the car carry lots of passengers or pets? 

Have you had traction (high voltage) Battery cooling air inlet checked for blockage?

[kithmo]

I would suspect the brake light switch, the switch may be too near or touching the pedal or faulty, the car won't accelerate when the brake is on and if the switch is on then the car thinks the brake is on. This may not throw up any fault codes.

Alternatively, it could be contaminated fuel, water or diesel in the petrol.

[flash22]

TBH it needs the codes from the inverter read - brake light switch is a possibility but if it's on it will usually put a brake override light on the dash

is this happening under Battery power or with the engine running ? What is the charge state of the Battery ?

A stuck, sticking caliper or handbrake may be another cause take it for a drive then put your hand near the brakes if one is hotter than the others that's the issue

[John Hof]

I both cases the traction Battery was extremely low on charge. it is 2016>. Checking was by Toyota Dealer. Will check the cooling vent . Thanks

Edited September 29, 2020 by John Hof
To respond better

[Catlover]

8 hours ago, John Hof said:

I both cases the traction battery was extremely low on charge. it is 2016>. Checking was by Toyota Dealer. Will check the cooling vent . Thanks

Checking and cleaning the vent on a Gen4 Prius is a 15 minute job, the filter is just behind the grille on the front of the rear passenger seat base drivers side, one screw and a few plastic fasteners. The hybrid Battery is sensitive to heat, if that filter is blocked, not only air bourne debris but also shopping bags, the hybrid Battery can get too hot and give up.

[John Hof]

Thanks Catlover. Cleaned the filter but not too dirty. On reflection I believe there was some luggage and wine purchases in the space behind  the drivers seat when the incidents happened