Oh by the way, speaking of Ford Tech Makuloco, since I can't help talking about him all the time, you didn't mention the mileage on your '07 but if it's > 60,000 you should absolutely, positively change the transmission fluid in the eCVT if you have never done so, and don't know if the previous owner(s) did. Yeah the manual says "filled for life" but that is a legalistic euphemism with zero basis in reality once the car is out of warranty. It is among the simplest of chores to perform on this car. Check your manual, it should say the eCVT takes either Mercon V or Mercon LV. I am guessing your 2007 will be MERCON V. Use the correct fluid, around 6 quarts. He has a video of it. You also might want to think about the 4WD system; I don't know what that entails in terms of fluid changes. Your car is looking really good (and you've got a trailer hitch!), you've got to keep her running!

 

And i agree. although i think my owner's manual says every 150k (that's crazy) - 60 k would make sense.
and i think that the 09 was the first for the LV (guess that fluid came out at that time) and the others are using V - but like you said: Need to check to make sure.

 

Well, futzing with the C4227A connector didn’t help; we went on a long drive last weekend and the wrench light made an unwelcome return. I did take the opportunity to plug in Forscan and monitor the battery temp while my partner was driving. The MaxTemp got up to 90 degrees F while AvgTemp hovered around 86 when the P0A27 code was generated. That seems a bit high for a 42-degree day, but didn’t get close to 131 degrees which seems to be the battery overtemp limit. It is in the range where the A/C battery cooling might be triggered, maybe a clue although it didn’t seem like the A/C was being called since the vehicle still went into EV mode. I remember the battery A/C was being called before I replaced the cooling fans and blend door motor.

I also pulled out the battery air filter while the car was in motion and checked that air was being pulled into the duct. Seemed like an adequate flow although it really wanted to pull air from inside the vehicle through the now-open filter access hatch rather than the outside vent; maybe some weird air pressure thing or maybe a rat made a nest in there.

I think my next steps are that I’m going to plunk down $45 for that replacement harness (thanks for the link!) and then open up the battery again, replace the harness and check the air path for obstructions. I’m thinking that the BCM module has already been reprogrammed since the engine is not shutting down from the P0A27 error. My guess is that the harness is supposed to address the root cause of the error, while the reprogramming downgrades the response to the error from a STOP SAFELY NOW with engine shutdown to a SERVICE SOON with annoying chime (every 10 minutes once it’s triggered, thanks Ford).

I’ll update in a week or two after the part arrives and I have a chance to work on this again.

Thanks for the tips on the transmission fluid change, I was reading conflicting info on whether this transmission is permanently sealed or needs to have the fluid changed periodically; no idea if the previous owner ever did that. I’ll probably have a shop do it on the next oil change since I only have muddy on-street parking available as a workspace. I’ll quiz them first on which fluid they plan to use.

 

From a few sources here on the forum over the years:
Optimum temperature for HV Battery operation is 82 degrees F
The HV Battery will turn on the Air Conditioner if the battery box is warmer than 85'F, but will still allow EV.
The HV Battery will run the Air Conditioner full time and dis-allow EV if the battery box is hotter than 100'F.
S Keith has said that battery box temperatures over 131 F are destructive to the battery.

You wrote:

Quote:

maybe some weird air pressure thing or maybe a rat made a nest in there.

.

Thinking about all this together, I'm wondering if you're seeing higher than usual battery temperatures (even on a cold day!) and it is being caused by some obstruction or failure of the rear A/C/fans/vent door to operate properly.

I think you should replace that harness, continue to monitor battery temps. and think about whether your battery is being cooled properly. I haven't monitored my own battery temps with FORScan this winter; but also my car is a 2010, in which the beancounters at Ford unceremoniously deleted the rear evaporator / outdoor intake, leaving the battery cooling to be handled strictly according to cabin temperature and the front evaporator, so my car's behavior might not jibe with yours.

I wonder if anyone else has some insight about whether your temperatures seem to be high, low, or just right?

In any case, going through with the harness replacement sounds like a reasonable next step.

And definitely do the trans. fluid. Ford Tech Makuloco is a straight shooter and if he says to do it, I do it. I'm betting your car is MERCON V, don't necessarily trust your mechanic, make sure you check your manual.

Keep us apprised and good luck. You'll find it. One thing at a time.

 

Update: No solution yet.

The 7M6Z-14A303-B harness arrived. First thing I did was inspect the thing to see what it does. It appears that the service harness simply transposes the wires into different positions, nothing more than that. I took an ohmmeter and checked that there are no internal jumpers or anything between the pins. I noted down how the wires are transposed; if anyone wants this info I can try to make some kind of graphic to convey how the wiring works.

I took off the rear battery cover, the one over the fans. From there I could see that this exact harness was already installed, which confirms that the “recall” was previously done. Unfortunately, to replace this harness requires taking off the other half of the battery cover, which I could not do because I was unable to loosen one of the side bolts using channel-locks; the bolt is on too tight. I would have to remove the whole battery unit to get that bolt off, and I don’t have a lift to do that. However, from the fan area I was able to poke around and see that the installed harness is in good condition and both connectors seated tightly. So I’m abandoning the effort to replace the service harness. After going through these steps, I doubt that it would fix the issue anyway.

While I had stuff apart I also took the opportunity to check the cooling system more closely. Requesting a BCM self-test via Forscan causes the fans to spin at full speed for about 15 sec, and I could verify good airflow in and out of the battery case. The self-test also opens and closes the blend door once so I could verify that is working. When the fans spin in the self-test procedure, the blend door is fully closed so it is only running air through the A/C loop. The fans don’t spin while the car is stopped, so there doesn’t seem to be a good way to verify air flow through the outside air pathway. Also it took me a while to figure out what happens to the air after it goes through the battery while using outside air. Many sources indicated that the air is discharged into the cabin which didn’t make sense looking at the ducting, but then I found one source that mentioned that it is discharged outside under the rear bumper near the ducting; I reached under the bumper and found a little grill with a flap over it, thus verifying where the air goes and confirming no apparent blockage. So as far as I can tell, the cooling system is working as it should.

More details on how and when the P0A27 error occurs: When driving on short trips around town or free-flow driving on the freeway, it doesn’t show up. Once about 30 minutes of stop-and-go driving are accumulated, then it will get triggered. Often the triggering event will be starting the engine after a short stop, like at a gas station. Once the error is triggered, and I am going to call this Grumpy Mode, the wrench light comes on while the SERVICE SOON message and lovely chime are issued about every 10 minutes. In Grumpy Mode, the scan tool registers only DTC PA027, and after clearing the code it comes back immediately, even with key-on engine-off. If the vehicle is parked for 4 hours, it’s still in Grumpy Mode; it will only go away after parking overnight and getting a good night’s sleep. After Gumpy Mode goes away, DTC PA027 is stored but can be cleared and won’t come back until the next time Grumpy Mode is triggered. This pattern does suggest something related to battery temperature, but I have been periodically checking the battery temps had haven’t seen any BCM temp parameter get above 90; Average temp is typically around 84.

Unless anyone has any further suggestions, I’m about to give up and learn to live with the annoying chime. At some point the battery may need to to be rebuilt and maybe that will resolve it. Meanwhile, as the weather is warming up a bit I’m up to 27 MPG...

 

If you have the time and the desire to do it, I'm sure it would be appreciated here as reference material with a good photo of the harness. Someone will use that information. I'm sure the harness itself will be valuable to someone in the future, maybe someone will offer to buy it from you. But the picture/diagram would be great. The more we know here on the forum in this DIY world of ours, the better.

This is excellent information and you answered one of my longstanding questions. Also very good to know, thank you very much! The article at your link is wonderful, I downloaded it and put it into my personal FEH folder.[/QUOTE]

That sounds right on the money. Except for Grumpy Mode. I'm glad to see the MPG is gradually improving.

My gut feeling is that somewhere you've got a temperature sensor / thermistor / circuit that is going out of range, turns on Grumpy Mode, lights the light and rings the dingdong. The problem is figuring out where that stupid sensor is. Maybe it's not even in the battery!

If it doesn't get worse and it doesn't go into Doghouse Mode, living with Grumpy Mode is a pain but it's not impacting the car's behavior. I'm stumped at this point. I wonder if SKeith has seen anything like this?

Thanks for your detailed replies, this is beyond my experience and diagnostic ability at this point, except to guess that somewhere a sensor is flaky or reading out of range, then when it cools down it's fine. I'm kind of ticked off that the DTC doesn't give any other extra status information that points back to the module/sensor/circuit throwing the code.

 

One more thought: Since you are experiencing this after quite a bit of driving, and then it takes a long time to "cool off" and clear the code, and you haven't changed the trans. fluid:

I rate it as an outside chance that maybe something is getting hot inside the transaxle where the electric motors live because of the age of the fluid, and a temperature sensor in there is ringing the bell. The transaxle and its motors/bearings/gears are cooled by the fluid as you can see from the fins on the bottom. I don't understand why that would necessarily throw this DTC, but it's worth a shot because you're going to be changing it anyway, and it's relatively cheap.

 

Minor update:
Still having the annoying P0A27 error. It's been ridiculously hot here in Seattle over the past few days with an all-time record high temp of 108 degrees F. On these hot days, our 2007 Escape is continuously in "grumpy mode" where error PA027 is constantly present and the SERVICE SOON ding comes every 10 minutes; an overnight cool-off does not make it go away like it does on cooler evenings. I had the transmission fluid changed, which didn't help this issue any but seems to be a good thing to do. Also recharged the A/C (it was kind of weak). The mechanic I went to mentioned the blend door could be causing this error, but this is the same mechanic that mis-diagnosed the battery cooling fan errors so I don't give him much credit. I suppose one possibility is that the blend door motor I previously replaced may have a bad proximity sensor, like it closes when battery A/C is called (I verified this is working properly) but the sensor isn't providing verification that the door is fully closed. This is a cheap part and I now have a tiny wrench to get to the bolts, so maybe I'll try replacing that sometime. Another thing I discovered in Forscan is the 'BPO Request' data field, which seems like it should be related to the P0A27 error labeled 'Battery Power Off Circuit', but it's status is always 'No' even in grumpy mode.

Another interesting observation, probably not related to the error: We went on some short drives in the afternoon in the 100+ degree heat. Before driving I felt the battery case with my hand and probably could have fried an egg on it, just from the sun beating down on the car, not the battery operation. Driving in this condition, the charge/assist gauge never wavered from 0 and the vehicle seemed sluggish accelerating from a stop and going up hills, like the computer didn't want to use the battery at all, which is probably a good thing. I didn't get a chance to connect Forscan until much later in the evening, and the battery Avg temp was 118F then. There were no new error codes or 'limited operation' data fields activated; battery was calling for A/C as it should.

 

Those were probably the hottest temps. the car has ever seen, thank goodness you're back down to about 65 degrees now in Seattle. Feeling (some of) your pain, where I am right now in the Northeast it's 94 degrees with RealFeel of 104, no wind, no breeze, no trapeze, and still going up. We've had three very hot days in a row and last night I forgot to put my Heatshade on: I went out to the car an hour ago and my A/C vent thermometer read 138 degrees.

 

I think I have discovered the first real problem that the PA027 error is creating. I had been wanting to run the battery re-balancing procedure for a while and finally had a relatively cool day with free time and unfettered access to the vehicle. I first cleared all DTC error codes (there were a few in there related to low voltage* in addition to the usual PA027), then I ran the Rbalance procedure via Forscan. It ran for about 10 minutes and then the wrench light popped up, the ICE shut down (EV mode), and Forscan reported “Rmode Suspended”. DTC PA027 was the only one present and is what triggered the wrench light. I tried to restart the procedure but it didn’t even start and Forscan reported something like “Rmode Aborted”. So it seems like I cannot run the battery balancing procedure with the persistent P0A27 error. Maybe in the dead of winter I’ll be able to complete the procedure before the error comes up, but for now it’s a no-go. I took a snapshot of the BCM data after all that and it showed battery SOC at 72% and Avg temp at 79F.

I’m contemplating whether replacing/rebuilding the HV battery is the only solution here and whether that would be worthwhile. Currently getting about 27 MPG in this 2007 AWD; the roof rack has been off for a while although my partner has been driving more miles lately and she has a bit of a lead foot and likes the A/C.

I’d like to be able to gauge the battery life remaining so that I could see how close we are to needing a replacement anyway. I’m going to put that in another thread since it’s a more-general question.

*I think the low voltage errors were left over from a camping trip a few weeks ago were we had our Escape parked for a couple days while we were sipping off the 12V battery to charge phones and using the interior lights. When we went to leave I couldn’t get the engine to start initially, but after turning off all the interior lights, turning the stereo fully off, unplugging all the chargers, then letting it sit for about 5 minutes, there was enough voltage to boot the computers and engage the HV battery. Lesson learned: Turn the key on periodically to charge the 12V battery when using the accessories for a period; even though this vehicle doesn’t take a lot of 12V amps to start, it seems sensitive to the 12V voltage level.