Ford Escape Automobiles Forum banner
1 - 18 of 18 Posts

·
Registered
Joined
·
151 Posts
Discussion Starter · #1 · (Edited)
During an interstate trip a few weeks ago I had a rash of wrench lights which I was able to ID via ForScan/Dash-mounted tablet as "Motor Electronics Overtemp" error code: P0A7C:00-28

  • First instance was during extended climb
  • it was HOT. Dash read near 100º
  • Both coolant levels fine
  • Pump was running - I could feel it and see return coolant flowing
  • Subsequent instances seemed to be limited to the combination of temps over about 96 and engine RPM near 3k - so..working reasonably hard
  • any time the lamp lit, I would pull off and wait 10m or so, hood up

Interestingly I discovered a severely degraded 12v battery later on (just before reaching the destination 2 states away) and wondered if it might have been causing enough voltage problem to throw sensor errors - appears the motor controller's sensor is a thermistor or something without discrete temp readout....BUT I got the same error light under the same conditions on the way back and again when a friend borrowed my car and immediately took it up a hill in the SFV during a 118º day (after I described my cooling issues in detail :roll: ) On the other hand, I've been able to make a number of high 90s trips without issue, including 102º just yesterday

My question is - do I have a cooling problem or is that motor controller cooling system inherently undersized? I need to find a good indy mechanic now that both CPO and hybrid warranties are long gone, and just curious if anyone else in hot climates has had similar issues
 

·
Premium Member
Joined
·
3,328 Posts
If you know you have a 12v battery issue, replace it first. A weak 12v battery will cause all sorts of problems.
 

·
Registered
Joined
·
20 Posts
Absolutely replace the battery, i had the transmission 'overheat' for a few seconds when i turned it in 115f weather every day, codes for a brake switch, it randomly thinking the parking brake was applied, just because of an old battery.
 

·
Registered
Joined
·
151 Posts
Discussion Starter · #4 ·
Oh I should have clarified; I had to do that en route. It was boiling enough for me to smell from inside and I put a fresh one in immediately. I had hoped that was it, but then had the same error lights on the way back, and once since.
 

·
Registered
Joined
·
151 Posts
Discussion Starter · #5 ·
Minor update; I after getting the wrench light a few more times in less extreme circumstances, it's seeming more likely there is a problem beyond borderline inadequate cooling for warm climates. I have ALSO discovered my A/C system leaks...not sure how fast yet. The shop that reported this wanted to replace 2 lines and the receiver dryer for $1700 :shock: and I had them just recharge it since they're not exactly a specialist.

This got me wondering if the issues might be related, since the the MECS radiator is stuffed behind the other two. I...just don't know enough about A/C to know if low refrigerant would result in a hotter A/C condenser, and if that's enough the MECS radiator immediately behind it from pulling any heat out of the coolant.

I have yet to see any other symptoms: MECS pump is circulating coolant every time i've checked and no engine run/electrical offline, disabled regen, and no outward sign of excess heat (one of the last times it lit up I was still able to hold a hand on the motor electronics unit...

When I line up place to do the A/C work (not real interested in amassing the equipment to do that on my own) I may try the nearest mountain pass to see if it's any less cranky.
 

·
Registered
Joined
·
34 Posts
My 2009 FEH has always done the exact same as you describe! Anytime it is super hot and I am driving long distance, I get the wrench. Always resets if I turn off/on. Never been able to figure out but I suspect you are right, something is just getting a tad warm.
 

·
Registered
Joined
·
387 Posts
="EscapeFromLA"Minor update; I after getting the wrench light a few more times in less extreme circumstances, it's seeming more likely there is a problem beyond borderline inadequate cooling for warm climates. I have ALSO discovered my A/C system leaks...not sure how fast yet. The shop that reported this wanted to replace 2 lines and the receiver dryer for $1700 :shock: and I had them just recharge it since they're not exactly a specialist.

This got me wondering if the issues might be related, since the the MECS radiator is stuffed behind the other two. I...just don't know enough about A/C to know if low refrigerant would result in a hotter A/C condenser, and if that's enough the MECS radiator immediately behind it from pulling any heat out of the coolant.

I have yet to see any other symptoms: MECS pump is circulating coolant every time i've checked and no engine run/electrical offline, disabled regen, and no outward sign of excess heat (one of the last times it lit up I was still able to hold a hand on the motor electronics unit...

When I line up place to do the A/C work (not real interested in amassing the equipment to do that on my own) I may try the nearest mountain pass to see if it's any less cranky.
From a retired lifetime 35+ yr HVAC tech, YES if you have a leak in the refrigerant system the pressures will go down on the suction side making the compressor work harder. Repair the HVAC first.
 

·
Registered
Joined
·
151 Posts
Discussion Starter · #8 · (Edited)
Ok well I have some updates but, as of yet, no good news.

I still have the issue, pretty exclusive to uphill grades - the wrench light will pop on and ForScan shows:

P0A7C:00-28 Motor Electronics Overtemp

There are no other symptoms, no Stop Safely now, no perceived change to electrical system involvement in driving, no excessive heat on the exterior of the motor electronics module (thought I'm starting some more in-depth troubleshooting with an eye on the inverter). So far I have:

1. recharged the HVAC system. While leaking, it seems to be slow as it has maintained much improved function while I get parts in and find someone I trust to do the work

2. changed the MECS pump ($230 from the dealer plus coolant) despite the old one seeming to run ok and was encouraged by what seemed like increased coolant flow back into the bottle, but as my test drive summoned the same fault code within 20m, I'm suspecting that was air.
*side note: dealer quoted about $800 to do this job, citing 2 hours labor, prompting me to time myself: 37 minutes including refill. c'mon guys

I also dug up an interesting thread at ForScan's forum that is mostly Fusion owners but a couple Escape people chiming in with similar symptoms;

https://www.forscan.org/forum/viewtopic ... 1&start=50

There's a lot of suspicion around air in the system and some speculation that the transmission fluid, in absence of a cooler that was apparently added to later 2013+ models, may be causing a cascade problem on longer drives by heating up MG1.

I'm now faced with an imminent road trip and need to hammer this out so my next steps are:

1. Flush and vacuum fill the MECS coolant which I hope will rule out air
2. Change the only engine coolant temp sensor I can find to change (on the transaxle) ...I highly doubt this is the one throwing the code but for $30 it seems worth removing the variable
3. Monitor a range of PIDs mentioned in the thread above to see if inconsistency shows among components in the MECS loop.

And I hope that helps because it's radiator or inverter time after that and I fear for my wallet
 

·
Registered
Joined
·
151 Posts
Discussion Starter · #9 · (Edited)
Well it doesn't seem to be air.

Nearest dealer turned out to be the first one able to do a vacuum fill ($213 JUST for the MECS loop, btw - I am absolutely buying the damn tool next time) and the following trip up the nearest decent hill summoned the same wrench light and DTC like clockwork.

side note; there was some disagreement between me and the service manager about whether the MECS and engine coolant loops were connected (he suggested both would need to be serviced at the same time - claiming there is a valve that allows coolant to intermix under certain conditions) .....he may have been right. The telltale is that the orange coolant in both bottles prior to my replacing the MECS pump has apparently been discontinued, and they use a more standard "yellow" (green) flavor now...after my test drive, both bottles show orange. So either there is indeed crossover somewhere or they really didn't manage to vacate much of the MECS loop before filling with the new stuff.

Anyway, I'm getting pretty frustrated. I'm supposed to be 2 states north right now, it's still 2 weeks before either of the dealers nearby can even LOOK at the thing, the indie hybrid specialist I found seems at least as busy, and no one else will touch it. I can try replacing the that temp sensor but, again, I can read that via ForScan and it seems within range. I'm concerned that this won't go away without a new radiator, motor electronics module, or inverter and have no current way of knowing which will do it. Those are big ticket items to be shotgunning and in the meantime I have a "4WD" suv that can't climb a 🤬 hill

EDIT: for any ForScan people, I can really only find 2 temp sensors to monitor via android (ForScan Lite) ECT (engine coolant temp) and MECS coolant, which only shows a voltage. ForScan thread noted above lists a lot more locations along the loop...I sort of suspect this is a buy-the-full-PC-version thing (which, in my case, means the PC, too) but if anyone [is even still hanging around here anymore] has a any tips there, I'm all ears.
 

·
Premium Member
Joined
·
1,143 Posts
I am not sure I would trust the dealer.

I don't know what year your vehicle is, but pre 2011 (mid year 2002 to mid year 2011) it was Gold. 2011 is a transition year, could be either (there should be a sticker on the degas bottle) Gold or Specialty Orange. 2012 was Specialty Orange.

How they can be out of Orange is beyond me, since a lot of current Fords still use it.

If this is a not the Gold but a generic fits all coolant that if you had Orange meets the spec WSS-M97B44-D (which is Dex-cool) then I guess good enough.

I know what Dex-cool does when mixed with other coolants, it isn't pretty.
 

·
Registered
Joined
·
151 Posts
Discussion Starter · #11 · (Edited)
I am not sure I would trust the dealer.

I don't know what year your vehicle is, but pre 2011 (mid year 2002 to mid year 2011) it was Gold. 2011 is a transition year, could be either (there should be a sticker on the degas bottle) Gold or Specialty Orange. 2012 was Specialty Orange.

How they can be out of Orange is beyond me, since a lot of current Fords still use it.

If this is a not the Gold but a generic fits all coolant that if you had Orange meets the spec WSS-M97B44-D (which is Dex-cool) then I guess good enough.

I know what Dex-cool does when mixed with other coolants, it isn't pretty.
2012 and came full of orange/pink stuff ....I certainly hope i haven't made a mistake by trusting the dealer(s) to use the right stuff. The bottle they sold me is "Yellow" VC-13-G, with both service manager and parts counter at 2 dealers mentioning the orange is 'discontinued'

I'm not really keen on relying on them to solve this either so I guess I'm buying:
• the service manual (I see a few listed in case anyone can vouch)
.....A: eManual Online ($27)
.....B: Factory Service Manuals ($13)
• some wireless thermometers I can stick on the DC-DC converter snd top of the transaxle (where I gather the motor inverter/controller is)
• a cheapo CL laptop I can run the full FORScan...I guess
 

·
Premium Member
Joined
·
1,143 Posts
Yup, that is apparently an approved substitute for Orange, and it can be used as a top off or drain and refill (no adverse issues if mixed).

I guess it has been over a year since it was superseded.
 

·
Premium Member
Joined
·
1,143 Posts
Yup, that is apparently an approved substitute for Orange, and it can be used as a top off or drain and refill (no adverse issues if mixed).

I guess it has been over a year since it was superseded.
 

·
Premium Member
Joined
·
1,143 Posts
Yup, that is apparently an approved substitute for Orange, and it can be used as a top off or drain and refill (no adverse issues if mixed).

I guess it has been over a year since it was superseded.
 

·
Registered
Joined
·
151 Posts
Discussion Starter · #15 · (Edited)
It seems pretty hard to get to but the only temp sensor I can find that's part of the MECS loop may as well get replaced, I guess. I'm already $450 in...what's another 30?

1756


EDIT: It's a cinch to get to, fwiw...just remove the plastic cover/skidplate between the bumper and driver side wheel (mostly 10mm bolts and one plastic clip) and it's right there
 

·
Registered
Joined
·
151 Posts
Discussion Starter · #16 ·
Another [frustrating] update. I checked out the temp sensor above, inspecting the harness (clean) and checking resistance, and unplugging to verify the PID in FORScan (the radiator fans kick on when you do this). I also found many more relevant PIDs in [I think] the traction control module, not the PCM, and proceeded up the hill that was reliably triggering my wrench light before...

...and of course it was fine. Here's the FORScan readout from the top of the hill on my second run:

1773


The Motor Electronics Coolant Temp, as measured by that sensor in the bottom of the transaxle, stayed rock steady and cold. The only thing I saw warming on a longer trend were the coil temps (motor and generator) which I understand to be cooled by transmission fluid, not MECS. The Generator Phase temp (upper right) recovered remarkably quickly...so I see no symptoms of marginal cooling loop function...at least not in fair weather.

This evening I guess I'm gonna open the bleeder screw at the top of the transaxle but if they did a proper vacuum fill (and for $213 I sure 🤬 hope they did) I fear this is more likely to introduce air than expel any of it. I'm running out of ideas...maybe a transmission fluid change but that never got above 170ºF ....?!?
 

·
Super Moderator
2015 Ford F-450 DRW
Joined
·
20,583 Posts
EDIT: for any ForScan people, I can really only find 2 temp sensors to monitor via android (ForScan Lite) ECT (engine coolant temp) and MECS coolant, which only shows a voltage. ForScan thread noted above lists a lot more locations along the loop...I sort of suspect this is a buy-the-full-PC-version thing (which, in my case, means the PC, too) but if anyone [is even still hanging around here anymore] has a any tips there, I'm all ears.
I am making the assumption your computer of choice is an Apple. You can run ForScan on a Mac but you have to purchase additional software. You would need to purchase Parallels software (Parallels Desktop 17 for Mac ) and of course you would need to come up with Win 10 or Win 11.

FORScan on Apple M1 - Parallels / Windows 11 Pro for ARM is successful & ELM327 - FORScan forum
 

·
Registered
Joined
·
151 Posts
Discussion Starter · #18 ·
Yeah...in light of the OTHER problems to solve, I'm not real excited about trying to get the hardware passthrough working for parallels and actually have a couple other reasons to have a PC kicking around these days anyway. Thanks, though

Speaking of other problems...

More wrench light (as expected) on my interstate trip, this time with a few more DTCs (i'll have to go pull the codes) including a specified 'location 1' for the overtemp, and very interestingly a "traction battery under voltage" warning...which makes me suspect that this all might be symptomatic of the NiMH pack getting tired. Just after the wrench illuminated, the highest temp in among the electrical components was the Generator Coil temp, up near 240ºF ...transmission fluid was running in the 180s (normally these seem to reach equilibrium about 30º apart)

...so I have something of a new theory:

HV battery voltage is dropping rapidly, as a result of cells going bad...particularly on a long climb where there has been no regen or excess engine power to supply charge current. Battery, management is demanding charge current to remedy the low voltage, in addition to current needed for the motor side (MG2) under load uphill. I think this is just heating up MG1 enough to throw the DTC. If I slow down or pull off, the temp recovers to within 30º of transmission fluid pretty quickly, and this whole time the M/G phase temps, MECS coolant temp and everything else have been steady and cool.

The rest of the trip I was able to avoid any more wrench light illumination by keeping the HV battery above 300V (requiring some 50-55mph hill climbs over with the semis)...and at this point, I think the MECS system is fine. Now I'm faced with somehow confirming the HV battery is to blame before throwing down serious cash for a new/reconditioned one (or serious time into adapting a LiFePO4 pack in if it turns out to be remotely possible).

I may change transmission fluid in the meantime but will be very surprised if that makes any major difference to operating temps. I'd hoped to get another few years from the HV battery so this is kind of a bummer if my latest theory is correct
 
1 - 18 of 18 Posts
Top