P0A7C criteria PCM parameter / wrench light?

[EscapeFromLA]

So I'm now having this issue with a 2012 Escape hybrid and have;

• Changed the MECS pump
• Vacuum filled the MECS loop ($213 at the dealer....next time I'm just buying the vacuum filler set)

But the wrench light (reading P0A7C:00-28 via FORScan) continues to be reliably summoned by climbing any hill that keeps the engine RPM near 3k for any length of time. I'm leaning toward swapping the temp sensor below as it's only $30ish but getting TO it seems to be tricky....I'd like to inspect the connector at least.

Has anyone gotten any farther with this? I'm supposed to have have driven a couple states north by now and have a '4WD' cuv that can't climb any hills. Dealers can't even make an appt within 2 weeks and based on the rest of this thread I kind figure i'm on my own

[EscapeFromLA]

Well I guess that's a "no" on anyone else getting further. I talked myself out of replacing that temp sensor because it's testing and reading fine...in fact last night's up the hill that reliably set off the wrench light last week failed to do so.

It took me longer than I care to admit to figure out all the transaxle temp PIDs needed to be access via different module (I'd had PCM up) but I loaded up the set below and climbed the hill with no idiot lights whatsoever. Readings just after the peak were:

Gen Coil Temp 198º (I saw this go to about 202º at most)
Mot Coil temp 183º

Gen Phase Temp 158º - this recovered VERY rapidly any time it climbed
Mot Phse Temp 102º

MECT 84º and stayed steady and cool the whole time
Transmission Fluid 169º

The coil temps changed very gradually and seemed to trend with the transmission fluid, appropriately enough. MECT was steady and low the whole time...it basically seemed entirely well-behaved, as confirmed by the absence of the DTC or dash lights...the bane of diagnosticians everywhere.

I'm debating trying the bleeder on the transaxle (inverter) but afraid that in light of my recent vacuum fill, it's more likely to introduce air than release any...but I'm sorta out of ideas. Radiator seems fine, [new] pump is fine, [new} coolant is flowing, doesn't look aerated...components seem to be cooling ok in cooler weather....at this point I sorta have to go ahead with my trip without solving this. I'll at least be able to keep an eye on all these when this inevitably crops up on the grapevine or southern OR

[Raylesk]

Been having this problem on my 09 escape when towing my 6x10 box trailer so in plumbing in a trans cooler using a 12v diesel fuel pump to see if it helps.

20211108_160611.jpg (816.19 KiB) Viewed 1631 times

[hueypilot]

Pulling a trailer is going to over work a CVT transmission. Change the tranny fluid every 30,000 miles will give more life.

[wr400f250]

Update for anyone who's wondering, my Fusion (my brother's now) is still going at ~270K miles. That's almost 200K miles with this issue in the heat of the Mojave Desert, still on the same transmission.

I recently purchased a 2010 Escape hybrid with the same issue, and will be moving into a new house soon with a nice garage. Once I'm set up I intend to install a transmission cooler/pump on the Escape and see if it fixes it. If it does, my brother will do the same on the Fusion. If that fixes both cars, we'll do our best to make up a list of easily attainable parts.

We noticed a definite pattern that the transmissions need to be heat soaked before ever getting the wrench light, so I think keeping the transmission fluid as cool as possible will do the trick since MECS coolant temp is definitely not the actual issue. That should keep phase temp spikes in check.