GSMacLean

There are multiple different pumps used on HF35s in various applications. This one is specific to the Energi.

Good luck. I would have your dealership look up to see which other dealerships show as having one in stock - that's how I found mine. That was back in April, and there were only two in the entire US. No idea if more have appeared since then.

12-14 miles or so, typically.

I hate to do it...but it's time for my 2013 C-Max Energi to go. 68,802 miles and in perfect shape with lots of recent maintenance. Whoever gets this car will be a lucky owner. You can see many more pictures and tons of details here: https://nerocam.com/2013_Ford_C-Max_Energi_For_Sale/

I had Ford search dealer stock nationwide. There were two dealers in the country that had one each, one of them was in Columbus, Ohio. I called that dealer up and bought it from them. They charged me almost double Ford's MSRP.

I've had quite a few people contact me and tell me that their pump had failed as well, so apparently it's going to become a more and more common failure item on our Energi's. Good luck finding a replacement! Incidentally, make sure you do get the correct pump - there are lots of sites on the Internet that list the pump but show a different pump, used on other Ford vehicles. The part numbers are very similar. The pump on the CMax Energi is unique to it - it is the only one that looks like the one in my picture. The exact part number is LX6Z-7P086-B Also beware of Internet sites that claim to have the pump in stock (which is almost all of them), but don't actually have the parts on hand, and simply order it from Ford after you place your order - and then a couple of weeks later realize that it is back-ordered from Ford with no ETA, and they cancel your order. Make SURE they actually have it in stock before placing your order, because virtually all of them operate this way.

I pulled codes from my car, and there were none. I was thinking it must be just a computer issue, so I did the default "fix computer issue" process: I rebooted it. I pulled the negative cable off the 12V battery, let it sit for ten minutes, then hooked it back up. Lots of settings and things got reset, but more importantly: it solved this problem. So I was right, it was a "confused computer" issue.

Has anyone encountered this before? Recently my 2013 Energi stopped detecting power usage when in EV mode. The blue instant MPG bar, pointed to by the red arrow in the picture below, stays pinned to the very top, no matter how much I accelerate. As a result, my Average MPG is stuck at 999.9 and never goes down. When the engine is activated, and this MPG bar turns white, it reads correctly, showing the instant MPG for ICE mode. But when it goes back to EV, it's back right up to the top again. I've tried resetting the MPG and a few other things, but nothing seems to change it. Anyone have any clue as to what might be causing this?

I just realized that I never came back here to update this thread. So the new pump was fine, and it did fix the problem. What was causing the issue to still show up was that I was testing the pump by sending it test values all the way from 0 to 100%, which the TCM never does. Doing so makes the TCM think something is wrong, and it throws the code again. In normal operation, the pump feedback is either 48% or 88% and that seems correct - at least the TCM is happy with those numbers. I've driven probably 500 miles since the new pump went on, and no more codes or problems, so I'm calling this fixed.

It took me over three months to find a replacement LX6Z-7P086-B auxiliary transmission pump to replace the failed one on my 2013 C-Max. If you're getting a P2796 code, this is usually the cause. Ford doesn't have any in stock, and there is no ETA of when they will be getting any more. Many parts suppliers on the Internet say they have them "in stock" and will "ship within two weeks." However they don't actually have any in stock - they order them from Ford when you place your order - and then two weeks later, when Ford tells them "sorry we don't have any," they turn around and cancel your order. Ask me how I know. I finally found the last two showing in stock in dealerships in the US, but neither were sure whether they actually had them, or just showed them on the computer. Desperate after having my car broken for over three months, I placed an order for both. And I got both. Of course. At over $400 apiece. I put one of them on my C-Max, which fixed my car. The other one I can't return, so I'm now selling it on eBay. https://www.ebay.com/itm/203895720445 If you need one of these pumps, this is probably your only chance to get one, at least for the foreseeable future. If that eBay listing is still active, then I still have the pump to sell.

Interesting...I had someone send me a more detailed Ford diagnostic document. In it, I found this...posting it here in case anyone ever searches for this information: Transmission Auxiliary Oil Pump check malfunction thresholds: P175A: TAOP circuit board temperature > 130 deg C for 3 sec. P0B0D: TAOP speed is > 105% or < 95% of commanded speed for 3 sec P0C27: TAOP current is < 0.5 Amps at 1000rpm to <1.2 Amps at 4000rpm. For 3 sec P0C28: TAOP current is > 12.5 Amps for 3 sec P0C29: TAOP current and speed meet conditions for P0B0D and either P0C27 or P0C28 for 3 sec. P0C2A: Pump speed =0 when commanded non-zero for 3 sec, OR circuit board temp > 135 deg C OR Overcurrent > 12.5 Amps for > 20 sec. OR Pump supplied voltage < 6.0 Volts or > 18.0 Volts for 325 ms. P0C2C: Duty cycle of PWM signal measured by TAOP outside the 10 defined zones of operation > 3.0 sec. P0C2D: Duty cycle of PWM signal measured from TAOP is < 9 % duty cycle for 3 seconds. P0C2E: Duty cycle of PWM signal measured from TAOP is > 91 % duty cycle for 3 seconds. P2796: PWM speed command signal on the separate control circuit < 80 Hz or > 120 Hz for 3 sec. The last one, which I bolded, is the one that interests me. I'm going to have to put my scope back on there while the pump is running and see just what the frequency is.

So back in December while out driving, my 2013 Energi, despite having almost a full battery charge, abruptly started running on its engine. Both EV modes were disabled (greyed out with an "X" through them) and the only option it gave me was "EV Later". Shortly afterwards, I got a check engine light. When I got home, I pulled the codes, and got a P2796:00 - here's what the service manual has to say about this: P2796:00 Electric Transmission Fluid Pump Control Circuit This DTC sets when the E-pump is not receiving a signal on it's PWM input signal from the SOBDMC / TCM . So the Energi has an auxiliary transmission fluid pump bolted to the outside of the transmission. Because the internal transmission fluid pump is driven from the engine, the car needs a way of circulating transmission fluid when it is running in EV mode, and the engine is not running. This pump is controlled by the SOBDMC, which is that big computer box on the driver's side in the engine bay that controls the entire electric side of the car. The SOBDMC controls the pump's speed by sending a PWM (pulse-width modulated) signal. The pump sends back a signal of some kind to the SOBDMC to let it know that it is working. If the SOBDMC doesn't see the expected "hey I'm running OK" signal from the pump, it shuts down the electric side of the house and forces the car to run on the engine only, to avoid damaging the transmission by running it without lubrication. When this occurs, it throws code P2796. So the Ford service manual has you pull the cable from the SOBDMC end and from the pump end, and check the wires to make sure there are no opens or shorts. I did so, everything checked out fine. I cleaned all the contacts and reseated everything. I took the car out for a test drive, and within a mile or so, it threw the same code again. According to Ford, the next "diagnostic step" is to replace the SOBDMC. Uh, yeah. Not only are those things crazy expensive, the labor to replace them is crazy (there's all kinds of coolant circuits and hoses), and they have to be programmed to the car. I'm thinking perhaps the pump is at fault. Why Ford skips that possibility in the service manual, I have no idea. So I pulled the connector at the pump end. There are 5 wires - unswitched +12v, switched +12v (ISP-R), the PWM control signal (TAPR_CT) from the SOBDMC and the diagnostic signal (TAPR_DI) to the SOBDMC. I put my scope on the PWM control signal, and using ForScan, commanded the AUX_TLF_PMP to actuate the pump. Here's what I saw: So clearly I am getting PWM at the pump. All the other lines (power, ground) were fine at the pump end. The pump was NOT running when it saw this signal, so I suspected the pump was bad. I ordered a replacement pump. I won't bore you with the story, but suffice it to say Ford doesn't have any, there were only two of them in the entire country, and it took me over two months to get it, at almost double the Ford MSRP. Today I put the pump on, and changed the transmission fluid for good measure. I went into ForScan and commanded the pump to run. Success! I heard the pump start up, and I could control its speed by adjusting the AUX_TLF_PMP value in ForScan. When the pump was running, the AUX_TFLPMP_FB (pump feedback) was showing 48.24%: When the pump was not running, this AUX_TFLPMP_FB number went very high, around 88%. Just as a test, I tried plugging the harness onto the old pump and commanded it to run. It did not run, and the AUXTFLPMP_FB value stayed at around 88% (the same as when the good pump was shut off). Plugging the harness back onto the good pump, it ran as expected. So that's it, happy ending, the pump was bad and everything is fixed, right? Not so fast! I cleared all the codes, and as a test, with the car in the air, ran it in EV Only mode, letting the wheels rotate in the air. It ran like this just fine for about five minutes or so, but suddenly the engine started up, and the car went back to "EV Unavailable" mode, and the check engine light illuminated. I pulled the codes, and sure enough, P2796 was back again. The strange thing is - the new pump is WORKING. I can command it. I can see in the AUX_TFLPMP_FB feedback that it can see the pump running or not. I tried resetting codes again and repeating the test, but it's still happening. So now I'm a bit stuck. I'm not sure what to check next. I don't know what type of signal the pump is supposed to be sending back to the SOBDMC, so I can't really check it to see if it is correct or not. The SOBDMC is seeing SOMETHING, because the value being reported for AUX_TFLPMP_FB is changing when the pump is running compared to when the pump is not. Anyone have any suggestions? Anyone fluent with ForScan with an Energi who could try commanding their pump to run and see if the numbers being reported for AUX_TFLPMP_FB are the same as I am seeing when the pump is both operating and not operating? I'm not entirely sure what to look at next. the P2796 code is for when the pump is "not receiving a signal on its PWM wire from the SOBDMC" - but it clearly is, because the pump is running as expected. The only way the SOBDMC would know if it is running as expected or not is through the feedback line, and it's obviously seeing SOMETHING there, because that AUX_TFLPMP_FB number is changing - but I don't know if it is changing to correct values. Open to suggestions here. Thanks for reading this novel! The very rare and hard to find pump installed:

You're being ripped off. Ford's own documentation says they are to book 0.8 hours for the whole replacement, including programming.

Same with me. It was a notification in my MFM app. If I log into MFM on the web, I find it in the "Announcements" section. Interestingly, and with the same carelessness they seem to have managed this whole process, they left the "Include link to schedule service" text at the bottom of the notice - but forgot to actually replace that text with a link to schedule service. What I find interesting is the wording "you MAY have the option to purchase..." Does that mean they aren't sure? Elsewhere it seems only 2014's and onward are eligible (why?). So was the sending of this a mistake? When I contacted Ford this morning, they were completely clueless, they had absolutely no idea what I was talking about, and knew nothing about this message. I had to explain to the Ford rep on the phone what "MyFord Mobile" was. Just pathetic.

I also just learned about this issue this morning when I had a message pop up on my cell phone. What a terrible experience from Ford. The wording was "you may have the option to purchase a 4G modem upgrade kit to be installed at your local Ford Dealer." So they don't know? They're just removing functionality the car was sold with, and the only way you find out is three weeks ahead of time via a cell phone app message? WTF Ford? I hate to replace my 2013 C-Max (I've got less than 50,000 miles on it!), but I use these remote functions ALL the time. My biggest question is, a few years ago when they swapped out the 2G modems, why didn't they skip to 4G at the time? Or a 3G/4G capable modem? It's not like 4G didn't exist at the time. The way Ford has abandoned my car and everything associated with it has really made me think twice. This is the fourth Ford in a row that I have owned, and I also have another Ford in my driveway now. My next car to replace my C-Max will not be a Ford. Here's the notification I received: