Thought I'd toss in some variables since I'm getting the code more frequently on my 2011 with 148K.

I drive a lot of miles. Like many it started showing on warm highway drives. But now exterior temps are 25-30° F.

I got a quality ODB connector & have run Forscan monitoring. It's hard to figure what is the trigger as all temps look okay but I've not found typical ranges yet & if there is a shorting spike or grounding, the software isn't catching it. I would expect bad wiring to be be teased by rough in town roads but I don't see the wrench being triggered that way.

The generator coil didnt go much over 150° after some 70+mph driving. I thought the gen coil hitting 150 was the trigger but then the next time the wrench appeared, temps were in the 140s. Previously coil didn't leave the 120s. At estimated wrench trigger point engine coolant was running at typical ~180, Trans was about ~110, motor coil ~125-140, mect was only 36-39.

Pump is good unless it's running & the flow is inadequate.

Now that I'm looking at all the saved runs, the generator inverter phase temperature numbers jump suddenly and reach 140 near the time of the wrench light. The change in temp is quick sometimes. High 90s to 111-115.

Whatever the trigger, it seems related to the extra overall temp & rpms of highway driving.

 

Seems like some wear and tear triggering one or more out-of-range conditions and the wrench light. Unless there is a software update that deals with nuisance lights caused by normal aging, i like the idea of looking at your engine cooling system to make sure it is running at normal temps. Changing the thermostat, engine temp sensor, cleaning the rad, changing the engine coolant, running 100% synthetic oil ( better lubricant/coolant), perhaps adding some Lucas upper cylinder lubricant to the fuel to help with friction etc are a number of inexpensive DIY options. Unless the problem is becoming epidemic, i don't think Ford will issue a TSB on a 10 year old + vehicle and a Ford Tech may keep lo$o$king and lo$o$king without success. Please keep us updated with this frustrating mystery.

 

Thanks for the background. Yes, it is strange. The other day the light came on after 45 miles of highway driving, I pulled into pick up an item for only about 2 minutes and started the car again and the car did not pull the wrench light again on the 50 miles drive home. I will try to do some monitoring in Forscan and see what I can learn.

 

Weber Auto & FordTechMakuloco have been great in understanding how everything works & maintenance. Until the Weber video I thought I had the metal band cvt & now understand the ecvt (mostly). The combination of those 2 got me thinking about the lubricity & wear of the old fluid especially after John Kelly pointing out how fast those electric motors are spinning per final drive gear revolution. 8 or 10 to 1 depending on generation. Those things are really spinning.

I just saw the FordTech ecvt fluid change video. I am overdue for that on my ownership cycle. I bought it around 65K miles so it likely could be on very worn out original fluid. I'll be doing that next week. I'm used to the old "don't mess with trans fluid" that I get even when I've requested it done by mechanics. Only my 95 Sable gave me transmission issues that had me panicked it was something bad. A flush later & all was well. I have a Toyota I'm going to drive into the ground. 280K+ with no drivetrain issues.

​I'll save some new data & compare once the fluid is changed out.

 

That is good info. I did follow his guide for ecvt trans fluid change. I bought it used at about 130k miles and the trans fluid wasnt dirty so not sure if it was done previously. It didn't solve the issue of overheating though sadly

 

No clutches to throw off material & darken it. Probably makes any metal contamination from wear stick out.

Well, I just read that atf "bakes" at higher temps & turns dark and is ruined. Is there a consensus on normal temps or what Ford specs are. I only find the post from the tow-er who says their near 300 degree reading is fine. That doesn't sound fine at all but I have little to compare at the moment.

 

I've been letting these variables & possibilities simmer in my mind since posting.

My inverter temp readings & the video of John Kelly's teardown of the Fusion inverter (transmission control module) has me focused & suspicious of that area.

I just read an old discussion on the Fusion inverter & they pegged the inverter peak at 140-150°. That lines up with one of my numbers & could be why the computer was concerned. 125° was the normal expected & the reason for separate cooling systems as the engine's higher temps aren't compatible.

I don't know how my 2011 Escape inverter compares to John's 2012 Fusion unit. I'm not finding a picture to compare very easily but I expect it to not vary much.

Those internal channels that look like a maze to increase surface area look like a choke point if hoses shed material internally. The channels are just parallel & not a maze but still narrow. Also the compound to mate the boards to the aluminum may be inadequate or breaking down.

Or maybe the high rpms are pushing/pulling more voltage than is needed to manage things & is what the pcm update is all about. Just managing things a little differently would stress the inverter less & stop those peaks. That unit is the real workhorse of these hybrids.
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I had forscan lite on a tablet with a USB adapter to monitor everything the other day. It was 25° out. I haven't gotten around to changing my transmission fluid yet

Previous runs had me concerned about the generator inverter because it had spiked high near the wrench light trigger. But mecs coolant temp is very low and those inverter temperatures drop quickly after spikes. The temperature control from the orange coolant seems to be fine across those temp sensors.

During my sustained highway driving the other day the things that concerned me are the generator coil, motor coil and transmission fluid temps. They kept steadily building the longer I maintained the drive. Both the generator and motor coil temps got into the 160s. Transmission fluid got into the 130s and all of them move down very slowly when speed was decreased. During the drive the main motor coolant temp got to 180 which isn't abnormal.

But other than engine coolant I'm not sure what these other temps should be. In one of the Weber Auto videos he mentions if the transmission fluid gets too hot that it could melt the coating off the electric motor windings.

What I'm thinking about now as a theory is if the transmission electric fluid pump is not working correctly or at all to move the fluid through the radiator for proper air cooling. At least I thought Weber pointed to an electric pump in the assembly. I'll have to go back and watch.

 

Alright, I think I'm definitely off on the last idea as I understand it, the trans oil is pumped mechanically off the generator shaft.

 

Is there a solution?