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I looked in the SM For normal HVB operating temperature and found the following. “With the ignition in the ON position and the engine running or OFF, the BECM monitors the High Voltage Battery internal temperature. There is also a High Voltage Battery inlet air temperature sensor mounted to the battery case which monitors temperature to the High Voltage Battery. The BECM uses the information from the various temperature sensors to control and maintain High Voltage Battery temperature by controlling the High Voltage Battery cooling fan. The ideal High Voltage Battery temperature is 25°C (77°F) with a desired range of 20°C (68°F) to 30°C (86°F).” The SM also mentions that if one gets a HVB over temperature PID set and the HVB temperature is above 95 F and fan speed is above 1500 rpm, the PID is most likely due to environmental conditions. I’m fairly certain that I read somewhere, the HVB will operate up to 45C (could be the trigger for the over temperature PID?). I believe the bottom line is: operate the HVB above the normal temperature range and expect a higher capacity fade rate.

1) yes 2) I think there may be posts on temperature in this forum as I can’t recall what the HVB temp limit should be. Unfortunately, the C-Max Energi forum which had lots of info apparently will not be resurrected / merged into this forum. Also, regardless of temperature, cycling from full charge to “empty” (hybrid mode) still reduces life. Read about Lithium ion batteries at “Battery University” on the web. So, those who charged twice or more daily (didn’t realize cycling affects capacity loss) suffered significantly more loss. 3) I doubt the charge cable matters. 4) The HVB cells IIRC in groups of 6 cells are automatically rebalanced. IIRC, there is also temperature related DTC data but IMO, you would want to stay significantly under those limits. I believe to rebalance pack you would have to replace the poorest performing cell(s) in a group (in essence rebuild pack). See link below. OBDSM1700_HEV.pdf

So, are you saying there is no noise with ICE on and car is moving? And there is no noise when in EV when moving? So, perhaps it is a bad damper. Perhaps with ICE on and stopped, the damper springs are shot and damper vibrates but once moving there is enough torque where the vibration stops.

Yes TSB is correct, Because the output / transfer shaft has to be spinning for noise (car has to be moving). If no noise from transfer shaft components, TSB does not apply.

Billyk24 is “spot on”. Unfortunately, it’s virtually too late to limit to 70% SOC when charging especially in hot weather as you’ve already lost about 1.5 kWh of capacity (5.5 - 4.0) or about 20% from the 7.6 kWh capacity when new. So, in order to mitigate further capacity loss at a high rate you would want to limit charging to 56% SOC (1-20%)* 70% which equates to a usable range drop from 4 kWh to about 2.2 kWh. Plus you would still have to do all the other things especially those related to temperature. if I owned it, I would not charge at all in the hot weather months and simply use the Energi as a Hybrid. In the cooler months, you can likely charge close to your current level (maybe limit it to 95% of 80% SOC or around 75% SOC. You might want to invest in the FORScan App so you can monitor data. https://forscan.org/home.html

I didn’t mention this in this thread but the large yellow dots indicating INL data represent the points on the discharge curve which Is the standard used to determine capacity loss. The standard test is to discharge the HVB at a C rate = 1 in a one hour time rate to the minimum cell operating voltage. The Ah rating of a new 1.4 kWh HVB is 5 Ah which would be a 5 A discharge rate. Since we as owners can’t easily discharge the HVB at 5A, I plotted the data in Amp ranges. The 0-10 A range encompasses the 5 A standard discharge rate for our HVB. My data appears to match the INL data points at the same miles on the battery. The capacity fade or capacity loss of the INL test vehicles at around 105k miles averaged 6.5%. I assume that my HVB has also lost around 6.5% based on my data. Below are 2 graphs showing this: average of 4 test vehicles and individual points of the 4 vehicles. I notice no difference in performance especially FE from new even now at 130k miles. The only difference I can document is that I have now seen SOC as low as 28%. When new, I ran several tests to see how low SOC might go in normal use. The lowest I could achieve when new was around 32%. I also believe the upper end of SOC has increased slightly but I never documented it (maybe from around 70% to 72%). I believe the algorithms expand the normal operating range (SOC range) as the capacity fades such that as the discharge curves fall, the available energy available for normal operations remains constant. Remember actual SOC is always measured from capacity when new. In other words, if the usable energy range when new was 0.64 kWh or 40% of 100% SOC , a 6% capacity loss would require the SOC usable range to expand to about 46% to keep the usable range of 0.64 kWh the same as when new. Bottom line is that I believe the Hybrid HVB will last several 100k miles before one might see a loss in performance (especially FE) as the operating voltage falls to close to knee of the voltage vs capacity curve. .

Here’s the issue with the 40k miles posts, the power train warranty applies. There is no indication what the issue causing the problem other than HVB not holding a charge (doesn’t sound like capacity fade). After 5 yrs / 60k miles the emissions warranty in CARB states apply and the Unique Hybrid Components applies in all states. I have yet to see where this issue was documented as capacity fade and covered by the unique components hybrid warranty. In all cases I have read about capacity fade, capacity fade was not warranted under the Unique Hybrid Components warranty. I don’t trust SA’s statements as applying to all the various warranties which cover the HVB. I understand about self correction typing but many mix up energy and power and it is a critical distinction in the Aloha post. Much like a lead acid battery not starting ICE in very cold weather yet having a higher SOC, a lithium ion battery may have a higher SOC (sufficient energy capacity), but not enough power to meet high demand requirement for whatever reason. Here’s a chart showing how under large power demands (high current) HVB voltage falls considerably. The algorithms will limit the power output of HVB, if HVB cannot sustain demand requirements and use ICE.

First, it’s 7.6 kWh of capacity. kW is power. kWh is energy. Second, here’s the details of the one HVB which I’ve ever seen replaced by Ford for supposedly non-manufacturing defect. Note the BOLD text I highlighted. One post, no details were provided as to why Ford covered it and failure may have been due to a manufacturing defect. It sounds like a power issue (kW not an energy issue kWh). There have many owners of Energis where Ford denied coverage under the Unique Hybrid Components warranty for capacity “fade”. “Aloha from Kauai! “Thank you Ford for replacing my HVB today!!! Love having my range back! Here's my journey: My 2014 energi Started having fairly significant capacity loss yr one that continued until last yr when I was at about 50% loss. Maybe i could squeeze in about 4 Kwh and it would use maybe 3.4 Kwh/ish. While Ford pushed back on the capacity loss, (I still think they should honor the 30% or more loss in 10 yrs or less industry standard) they did listen and act on the performance issue is was causing. It would not stay in EV only mode and when accelerating it would only utilize about 1-bar of EV power causing almost a super short stall or mini jarring lag in what is normally smooth and strong acceleration. BTW they did change out the battery module first to rule that out as an Issue. I hope this helps a lot of owners. If your really stuck don't forget to reach out to some the community colleges that are rebuilding EV batteries for cheap or some work around. Onward steve parsons Kauai” https://fordcmaxhybridforum.com/topic/7997-cmax-energi-hvb-battery-replaced-under-warranty/

The C-Max Hybrid Battery. ? The same cell chemistry is used in the Energi HVB. But obviously, some HVBs will have shorter life and others longer life depending on how the HBV is used significantly more so in the Energi than the Hybrid. Typically end of life of a HVB is defined to be when the capacity “fades” to a % of it’s new capacity irrespective of cause. On of the reason I didn’t by an Energi in 2012, was the potential issue of significant capacity fade in the Energy ( which directly affects usable EV only miles). Capacity fade in the leaf was well documented in late 2012. Given the strategies one would have do to mitigate capacity fade in the Energi diminished its plug-in value. Unfortunately, Ford did not warrant capacity fade and did not inform consumers of the potential for capacity fade if the Energi is fully charged twice a day in hot weather. Here’s a graph I put together some time ago for 8 Energis tested by Idaho National Labs. I believe all were used in Phoenix for courier service. It’s clear the shape of capacity fade for the Energi shows increasing fade with mileage likely due to cycling to full charge in hot whether. https://www.autoblog.com/2012/12/20/ford-key-life-test-advanced-plug-in-vehicle-batteries/?guccounter=1&guce_referrer=aHR0cHM6Ly93d3cuZ29vZ2xlLmNvbS8&guce_referrer_sig=AQAAAEEAM7Me4c28-r5oiIVezpV4s9obAXWN35BRdGySHrHEJr3g2dynee5_H-DWF9YAs4q579PLsWMiPDMpMeRrqtMZxgy0rfhk8WW64kjXF92hTwaMNQC0Ca21zwXnYJ4yGOkjtMEzn7ooem0DOnRJVCGSOKQ8UGrRO02ERshmD6sM

Great news.

Just so you understand, to open up transmission, the power train must be removed from vehicle as a unit even to replace RTV sealant. Expect about 10 hours of labor. So, you want to make sure that it will be covered under the unique hybrid components warranty which is 8 years / 100k miles or an extended warranty, if you have one. I doubt the RTV leak will be covered though.

If you have a button for Active Parking Assist, then you have both front and rear parking aids (sensors). The Service Manual says with respect to the parking aid system (includes both front and rear sensors): "The parking aid system is enabled and disabled through the message center, located in the IPC. Disabling lasts one key cycle." I do not have the front parking sensors, a rear view camera and an active parking assist button on my SEL. Also, if the front sensors detect an object, the sound will come from the front speakers. The Owners Manual does not show a virtual button in the IPC displays for the front parking aid. Since you have a physical button then you have Active Parking Assist which requires both front and rear parking aid sensors. But IMO, that button should not turn off the parking aid sensors as one still wants to know when objects are near even if one does not want use the active parking assistance.

I looked in the Service Manual and disabling the rear park aid (and audible alarm) is only suppose to last one key cycle. So, don't know whether cycling rear parking aid in left cluster will solve problem but it might since the IPC was updated. Also, the sound comes from the rear speakers. Are rear speakers working?

Here’s pic from 2013 owners manual.

Here’s a pic. If you turn it off, no beep but radio will still reduce volume.

Turn your parking aid on in the left had display.? It likely defaults to off when the IPC was updated.

Guys, the first thing you need to do is to scan your car for trouble codes with a scanner like the FORScan App which can scan all ford modules, run diagnostic tests on modules, and monitor / record PID data. https://forscan.org/home.html

Not true.? There are 3 ANC microphones, located in the left front , right front and rear in the cabin headliner, which are inputs to the digital audio control module via a connector under the glove box. There is one SYNC microphone (voice) located in the overhead console which runs through a different connector under the glove box and is an input to the APIM.

You can reset battery age by the method in this link below.

1) 12 V batteries like to be fully charged. 2) The C-Max charging algorithm does not act as a "fast" charger (takes long time to replace several Ah of use). 3) Allowing C-Max to set for extended periods of time drains battery. 4) It's possible dealer did not reset battery age parameter such that the PCM believed the max. capacity (Ah) your 2019 battery was significantly lower than the actual new battery capacity. Thus, battery will be charged at a lower voltage than it should be charged at. So, it's very likely that given the above or combination of the above, your new 12 V battery was always at a very low state of charge because it wasn't driven very often for long times. So, yes allowing the 12 V battery to be at a very low SOC and perhaps charging at too low a voltage can cause sulfation and premature failure.

The INL statistics are on the INL website. Both hybrid and Energi have a mechanical transmission oil pump which is driven only when ICE is running. The Energi also has an electric aux. transmission oil pump. The taxi transmission issue is TSB 14-0024. The 0024 specifically applies to hybrids in Taxi service. Later in 2014 Ford issued TSB 14-0176 which superseded 0024 to include all hybrids and Energis. My guess is that the issue causing the transmission issue is exacerbated by the type of service the INL test vehicles and taxis operated under. Ford has always stated failure may occur if operated under certain conditions yet fails to describe such conditions. I still believe it is related to changes in axial load (trust) on the output shaft due to regeneration EV operation. The direction of axial load (trust) on the output shaft will shift from EV operation to regeneration. If one looks at pics of the shaft one can see the helical gears on the output shaft. The bearing retainers have to hold the gears in place and not allow the shaft to move as it does when the transmission fails. Perhaps this constant change in direction of axial load eventually overcomes the hold force of the bearings and the shaft starts to move. Perhaps its related to number of cycles of this shifting / of axial load and the magnitude of the axial load. In addition, the lack of cooling / sufficient lubrication inside the transmission when in EV and regeneration (ICE off) might contribute to the issue. But Energis have also had failed transmissions. I guess the bottom line is if one does not know how vehicle was operated, I'd only buy a newer model of a model with a replaced transmission ( both after the build date in 2016 which we believe may have a transmission which mitigates the issue) or heavily discount the offer price otherwise.

I agree, as we are not seeing “tons” of HF35s failing. We really don’t know the failure rate. Some believe it is very high based on the INL failure of 3 out of 4 C-Max test vehicle transmissions. A quick tally shows that Ford sold around 225,000 vehicles with HF35 transmission in 2013 and 2014. Total sales are likely around 500,000 vehicles with the HF35 to date. IMO, the primary reason potential owners should be concerned about the HF35 failures is the very high cost of replacement should the failure not be covered under warranty. Of course as vehicles accumulate 100k miles the likelihood of any part Failing increases. I monitor(ed) the Fusion and C-Max Hybrid and Energi forums since 2012. Based on reports of failures in the forums, I doubt the failure rate is any more than several % points. There have been very few reported failures in the forums. As an example, VW TDIs had HPFP failures due to contaminated diesel fuel which were not covered by warranty. Less than 250 failures were reported in the forum out of about 100,000 early units sold. Actual failure rate reported to NHTSA was around 3.7%. So, around 6.7% (250 /3700) of actual failures were reported in the forum. So, using a transmission failure rate of 5% and the 6.7% number, we might expect as many as 750 transmission 2013/14 failures reported by members of forums. No one, AFAIK, has tabulated the reported failures in the Ford forums, but IMO, it would be less than 750.

There have been comments by owners that the CARB hybrid warranty does not cover the transmission. Second, there are reports that Ford's unique hybrid components warranty may not cover bearing failure on the output shaft which is the most common cause of transmission failure which is covered under the 5/60 powertrain warranty. The C-Max is a great car. But, you need to find out whether the transmission has been replaced. Probably worth a CarFax report to see if it notes a replacement.

Search this site or internet for unique hybrid components warranty. Unless you are in a State which follows "CARB" warranties the car HVB is warranted for 8 years 100k miles (10 years / 150k miles in cARB states). Also, look up Ford extended warranties. You can price them on line at at many dealers like Flood Ford iirc. I don't believe Ford will sell one if you did not have one initially for the first 114 k miles.

50 days of 110F + and C-Max AC handles it with ease in full sun. AC load running around 1500 Watts once cabin cooled to setpoint temp. Turn set point temperature to minimum. Measure the temperature out of the center vent. Within a minute or so temp should be in the lower 40s F. If above 50F, there's an issue. Compressor is turned off if evaporator core reaches about 35.6 F.