I drive six miles to and from work. When I drove home last night it was about 15degrees, which is about 20 degrees warmer than it has been before when the assist was working just fine so I'm not thinking it's the temp. I don't have any kind of scan gauge to check on all this. Also for the last few weeks when I drive to work it's acting like the thermostat is stuck open, it keeps the car at 2500 rpm in a 45mph zone which is almost 1000 high. It has also been seemingly doing a recalculate for a week or more as noted by the charge/discharge gauge when the throttle input is constant. Hoping someone can give me some good feedback on what may be going on and the path to take. I like the car other than the recent problems, so I don't want to have to trade it in.

 

I can only guess because you don't have a scanguage and the ability to view the hybrid battery temperature (Tav). From my experience, when the hybrid battery pack gets too cold, it may go into a series of charges/discharges in an attempt to warm itself-raise the Tav temperature. When this is occurring, there is little or no battery assist and the ICE runs more than usual. I have had this happen but only infrequently and only during very bitter cold (single digit or colder) winter weather. Normally use of the engine block heater and hybrid battery heater during the night, will raise the Tav temperature enough that sitting outside in bitter cold winter weather is not an issue. But, if my GFI outlet in the garage "trips" during the night, then I may have this issue.

It helps to have a scanguage for more than one reason.

Good luck.

 

My '05 has been acting exactly the same way with our sub-zero temps last week. I agree that it's probably a cold HV battery. Once my HV battery got warmed up, things acted more normal.
I bought a scangauge within a couple of weeks of buying my FEH last fall. Best thing I ever did.

 

My 2005 FEH acting the same way.
AT 2500 RPM can see 25 MPH to 55 MPH till HV battery is warmed up.

 

While the following explanation makes perfect logical sense there are a few here that are in full denial.....

Ford has a US patent that pertains to the use, non-use actually, of regenerative braking as/when the OAT declines to freezing and below. Note that it is unlikely that the patented technique is used other than during "automatic", non-driver induced, regenerative braking.

You may have already noticed that should the TC system sense impending or actual wheel lockup during regenerative braking it will immediately switch to frictional braking. Regenerative braking applies ONLY to the front wheels and thus switching to frictional braking not only allows for ABS activity it also more evenly distributes the braking effort over all four wheels.

Since front braking only can lead so quickly to loss of directional control Ford is reluctant to use a high level of regenerative braking when conditions are such that doing so would/might be fraught with peril.

If you wish to test my theory then locate the OAT sensor and bypass it with, say, a 1000 ohm resistor.

Caution: Be fully aware. Using this technique might well result in an inordinant level of regenerative braking in conditions where otherwise the system would automatically over ride same.

 

What has your answer got to do with the question/problem????

 

Please just ignore him everyone, he has a tendency to derail every thread he goes on very inconsiderately. I hope we can just act like he's not even posting so I can get to the bottom of this.

 

[quote=hondarider90;246664]I drive six miles to and from work. When I drove home last night it was about 15degrees, which is about 20 degrees warmer than it has been before when the assist was working just fine so I'm not thinking it's the temp. I don't have any kind of scan gauge to check on all this. Also for the last few weeks when I drive to work it's acting like the thermostat is stuck open,

it keeps the car at 2500 rpm in a 45mph zone which is almost 1000 high.

The ICE is kept well above the normal (>33F ambient) RPM in order to provide enough "drive" torque and charge the HV battery simultaneously since normal coastdown regenerative braking is not "fully" available.

It has also been seemingly doing a recalculate for a week or more as noted by the charge/discharge gauge when the throttle input is constant. Hoping someone can give me some good feedback on what may be going on and the path to take. I like the car other than the recent problems, so I don't want to have to trade it in.[/quote]

Since the ICE does exactly the same thing with a long distance constant speed highway trip with no coastdown periods to charge the HV battery why is this so difficult to understand?

 

Tyler, ignore Mr. West's reply. For four years now, we have provided him with data from several members disproving what he posts. He does not have a FEH, much less a service manual. There is no documentation that what he has posted has been implemented in the FEH. He posts the same way over in the Toyota forum where other members have called him out.

Your issue is related to the cold temperature of the hybrid battery pack.

 

Data..?? Disproving...???

Other than personal statements, opinions, what data....??

Not even I would attempt to "prove" that regenerative braking is "derated" in cold climates.

So I'd leave that task to the fools.

Oh, you can walk into any Ford dealer and get an owners manual along with a quiet place to read it.

Some dealer service managers will even give you free and open access to the factory shop/repair manuals.