Nothing good, I'm afraid.

I have done a bunch more hot weather driving including triple digits this last weekend, continue to have the indicator light up, and continue to have no other symptoms;

- It's getting more sensitive; I have had a instances of the wrench lighting up in mid 70s (F) outside temp (where it used to require high 80s)
- Gen phase and coil temps are the hottest amongst what ForScan will tell me (as much as 112ºC) - coil temps still generally track about 20C above trans fluid when working
- MECS temps are low (high 30s to mid 40s C)
- Battery continues to behave, apparently (good voltages, temps below 40ºC w/ cabin-air-cooled pack in 2012) ...but OTOH it would be astonishing if a 13year/130k pack didn't have significantly degraded performance
- no SSN, no additional codes, no noticeable behavior change including regen braking before/during/after
- I do find it noticeably more likely to occur on an incline....I can cross a hot SFV at 75mph and have the wrench light up the second the road pitches up the Newhall pass (100% reliable there)
- light extinguishes when ignition is cycled even while everything's still hot

I hate to say it but I'm getting to the point of resorting to the ol' Car Talk® electrical-tape-over-the-idiot-light solution (what fault light? I don't see a fault light...) I have stopped making any kind of driving accommodation around this light and have yet to see any consequences.

Annoyingly, I need to take mine for likely PTU replacement (was rather hoping it wasn't that, but there is a persistent speed-related bearing noise and I have already replaced the ENTIRE front end including both knuckles and CVs).....so I am on the lookout for a hybrid-savvy indy mechanic and will certainly ask about this issue. I may also try to write Ford (pause for laughter) just to see if anyone might respond about what is TRIPPING that code, and if it is (as I suspect) a derived temperature from other electrical readings in the drive system, since there is no measurement pattern or threshold that I can detect.

< insert shrug here >

 

Have you found any negative impact on performance (e.g. fuel efficiency or acceleration)? It seems my Escape's fuel efficiency has gone down (sub 25 mpg).

 

Heh - I just came back to edit that I still see as-expected MPG (28+ combined, pretty decent for AT tires and taller H&R springs). No issues around town (regardless of outside temp) and even made a fairly recent climb to around 6000ft on a slower road (45mph speed limit but curvy enough to average a bit a below that) without any complaints. Seems to require freeway speed....which says "transmission fluid involvement" to me

 

Seems like my fuel efficiency is going down. I spoke with a mechanic who says he's encountered this issue before, mentioning something about air cooling not getting to the battery (he mentioned a fan), and that it'd cost me around $900 to fix. He also mentioned that it's good the car hasn't gone into limp mode but from others' stories on this thread, it doesn't sound like people have had problems with limp mode.

 

Are you able to keep tabs on battery temps en route? I still tend to think battery related issues are going to produce different codes than the one in this thread. The one battery overtemp episode I experienced resulted from a bag falling over and blocking the exhaust vent (I wish they'd run air across the whole pack and out the other side below the rear window, like where the intake is) during a long descent several years ago. I think I only noticed because the ICE was kept running, and subsequently that the battery was largely offline (no regen, traction current coming from MG1 only...hence engine run)....I believe the 'limp mode' would have produced a lot more lights on the dash and display, and it certainly wasn't SSN.

i've monitored battery temps (highest and lowest cell temps, via ForScan) on a dash-mounted tablet during the last bunch of climbs and have mostly seen 90s F....low 100s on very hot days. That doesn't seem overly concerning to me, so I haven't been troubleshooting the battery cooling system (just air in my 2012)

Also FWIW I'm pretty sure there's a battery fan PID