Hybrid battery degradation

2010 FORD FUSION
129,000 MILES • 2.5L • 4 CYL • 2WD • AUTOMATIC
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DLEETE2
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I have the car listed above hybrid which goes into electric vehicle mode at speeds up to 47 mph. I can no longer push the throttle down as far in EV mode before the gas engine engages. EV mode operates like it does when the outside temperature is really cold even when it is 80+ degrees outside. I have had the vehicle for nine years so I know how EV mode operates in various temperatures. I took it to the dealership to run diagnostics and they said the hybrid system is operating as normal. Is it possible that there is a hybrid battery temperature sensor giving a false reading saying that it is colder than it really is? The dealership said it could be battery degradation but I can still drive just as far in EV mode as I did when I first bought it; I just cannot push down the gas pedal as far without the gas engine engaging. It is extremely noticeable now when then temperature is below 60 degrees (F). The gas engine is on constantly except when I apply the brakes and then engages immediately once I let up on the brake pedal.
Oct 12, 2018 at 4:10 PM
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DANNY L
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Hello, I am Danny.

That does not mean anything about the Hybrid battery. Your car has a (Fly-By-Wire) Accelerator Pedal Position Sensor. It acts as a Potentiometer and is attached to the (gas pedal) accelerator. It is possibly giving the cars engine and computer false readings giving you the symptoms. I would suggest having that checked out. I have attached a picture. Hope this helps and thanks for using 2CarPros.
Danny-
Oct 15, 2018 at 4:43 AM
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STRAILER
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If I can jump in here, this happens when the throttle actuator gets dirty and the PCM and the actuator lose their correlation which puts the car in limp mode. Here is a guide to help you clean the actuator. Disconnect your battery first.

https://www.2carpros.com/articles/throttle-actuator-service

Please let us know what you find. We are interested to see what it is.

Cheers, Ken

Oct 15, 2018 at 11:24 AM
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