Had 2 instances this week where my 2006 Escape Hybrid will not start after sitting in the sun for 2+ hours on days where the temps went over 90. First time - towed to dealer, started fine the next day and they can't replicate. Second time - I turned on the heater and it started after 5 minutes, drove it to dealer and they can't replicate. What could this be?

 

Can't tell what's wrong from such limited info, but it's probably NOT the weather.

 

If this was a conventional car I would say go clean up the heavy duty wires to the starter motor. I have identified by experience a symptom with these cars of starts fine cold & won't turn over the starter hot as a dirty & oily cable connection at the starter motor terminal. Not the same here.

I have noted many posts about failures that cannot be replicated later. In response to these I have posted info on dirty or loose connectors to little response.

My experience of 30 years on ships is that when you start getting things like this, it is not a "hard" failure but somewhere in the wiring.

When you go to start the FEH a 12v contactor picks up to enable the HV battery to spin the motor in the transaxle that starts the engine. The few clues as to symptoms you give make me think it might be in the 12v side powering this contactor. Go follow these wires, make sure they're clean & tight.

 

Following that thinkning, could the 12v batt be getting weak? When it's hot it has say 9v (random #) but when it cools off it has enough to close the relay?

 

So, what exactly happens when you turn the key?
Does it turn over, but not fire, or go clickety click, or what?

Any prominent dash lights?

 

Thanks for all the great ideas. Got a few questions about what it sounded like when I tried to start the 2 times it wouldn't start. I get the same usual sounds of what I think of as the "hybrid sound", clicking/humming etc just like normal. Windows, radio, heat/ac all work. But when I turn the key I get nothing, like having an absolutely dead battery (the battery has been checked and is fine). On my message window it says something like "stop car safely", as if it thinks I'm driving. The oil and engine lights come on.

I'm admittedly frustrated that the folks at my Ford dealership don't know what to do with me. They basically gave me the car back (twice now) and shrugged their shoulders as they could not replicate the problem. Have had multiple times since Sunday and Tuesday (the 2 no-start days) that all has worked fine, as if no problem. Temps have been down again, leading me to think there's something to the heat theory... We'll be driving Palm Springs in 2 weeks, that will certainly test the theory so I'd probably better figure out where to tow it if needed. I appreciate all the ideas, thank you.

 

For 08hybridok: lead acid batteries have increased capacity as temps rise, so I don't think its that. You might pop off that cell caps and ensure the water level is right but I don't think its the battery itself.

The no start with all the normal clicks, hums, or whatever, tells me the problem could well be with the 12v circuit that picks up a relay to enable HV to the transaxle to spin the ICE. It sounds like the wiring to the relay could be dirty,oily, corroded.

As I mentioned above I have seen the no hot start with conventional cars systems and the fix turned out to be cleaning up the heavy cable to the starter motor. The symptoms here are different and the current carried by the circuit to the relay is far lower than a conventional starter, but the issue appears to be something in the circuits that enable HV from the traction battery.

Its the best I have, given the symptoms. The alternative is to look at the HV wiring... I'm not ready to do that kind of stuff. Hopefully the Ford folks did look over that wiring when you had it in.

 

Windows closed up tightly, BRIGHT sunlight , 2+ hours....??

Dark interior...??

Cabin temperature might have risen to extraordinary levels...

"...turned on the heater...."


I suspect you mean turned on the heater blower to help exhaust the heat, mayb eevn lowered a window or two..??

So I suspect your experience just might be SOP. To protect the solid state electronics from going overtemp if not the hybrid battery also.

 

I don't think so. 90 is hardly hot... My car works fine in 115-118 degree temps.

 

"...my car works fine in 115-118 degree temps.."

Inside the cabin or outside....??