Lift gate AND 12v Battery

[stratosurfer]

All,

My 2013 C-Max Hybrid has 115,000 miles and within the last four months the rear lift gate started acting erratic. On a push from the console it will go up a little bit and then go back down and not lock. Then a second push will sometimes send it back down for a lock, or partway back up. And once it starts traveling up after possibly multiple stalls, it will finally make it all the way up. It does this on the console button, and on the fob as well. Sometimes it goes, struggling, all the way up the first time. It seems to go from the all the way up position to closed most every time (80?%). I took it to Ford last week for a diagnostic and they told me they could not replicate the problem. I was -disappointed-... and asked them to try some more, they did and ultimately did not find -any- codes being thrown, and they mentioned if it were the electric liftgate strut going it throws a code. So after all this and 3 days of review, they said the only conclusion they can come to is that my 12V battery needs replacing, yet they didn’t seem super confident in this diagnosis. So much so they did not charge me the normal 1 hr diagnostic fee. They said the aux battery is the original one and now well over 5 years old. As well after the car is turned off, the electronics quickly shut off with that message ‘Turning off to save battery/setting’ or something as such. The theory they floated it that the aux battery holds the positional settings of where the liftgate is positioned. I have had the Liftgate alarm, that it is ajar come on while driving down the freeway and for no good reason (no cargo back there).

Can anyone comment on having a similar problem? I don’t mind replacing the battery, it is a little of a pain, and I was going to go ahead and put in an Oddysey as I have super experiences with them, but I don’t want to put in a premium battery if this is not my problem.

Any help or comments appreciated. I’m certain the dealer is giving me their ‘Best Guess’ diagnosis based upon no codes.

Thanks in Advance for the help.

[plus 3 golfer]

.. they said the only conclusion they can come to is that my 12V battery needs replacing, yet they didn’t seem super confident in this diagnosis. So much so they did not charge me the normal 1 hr diagnostic fee. They said the aux battery is the original one and now well over 5 years old. As well after the car is turned off, the electronics quickly shut off with that message ‘Turning off to save battery/setting’ or something as such. The theory they floated it that the aux battery holds the positional settings of where the liftgate is positioned. I have had the Liftgate alarm, that it is ajar come on while driving down the freeway and for no good reason (no cargo back there).

C

...I don’t mind replacing the battery, it is a little of a pain, and I was going to go ahead and put in an Oddysey as I have super experiences with them, but I don’t want to put in a premium battery if this is not my problem.

..

Is the car "on" when the liftgate acts erratic?  It would seem that if yes, then your 12V battery may not be the problem as the DC/DC converter would be supplying 14.7 V to the 12 V system.  If "no" then, 12V battery may be the issue (see below).  

 

There is a rear gate trunk module (opens and closes lift gate) that communicates with the BCM and the BCM / trunk module likely do store the lift position (not the aux. battery).  But, most modules will retain data even if low voltage or no voltage. But, operating a motor on low voltage can be problematic.

 

There is a "latch secure" contact closure signal to the trunk module which likely would stop the closing of the lift gate and signal to the latch motor to secure the lift gate.  This BCM also uses this contact for monitoring lift gate ajar.  My guess is the switch / latch might need adjustment if you continue to get the liftgate ajar.  There are several DTCs related to the power lift gate but this note from the Service Manual supports the techs diagnosis:

 

NOTE: The power liftgate may not operate correctly under the following conditions:

• A low voltage or drained battery.
• A disconnected battery.`
• Repairs/adjustments have been made to the power liftgate rod, power liftgate motor, liftgate hinges or liftgate striker. 

Since your battery is 5 years old, I'd replace it.  If you do get an Odyessey, get one that is the same (close to) Ah rating as the Motorcraft AND reset the battery age PID (ForScan Windows App will do it).  Otherwise, the Battery Management System including the charging algorithm will make incorrect assumptions as the battery ages.  As the new 12 V battery ages, absent the reset, it will likely not be charged to the State Of Charge it should be charged to.  

 

The message - Turning off to save battery - is an indication of low 12 V battery SOC primarily due to battery loss of capacity as the battery ages with use. If a new battery is put in and the battery age is reset, one can run the radio for 10 minutes after key off before the message appears.  The battery age reset will zero out the coulumb counting algorithm (integration of current into and out of the 12 V battery) used in determining SOC of the 12 V battery.

Edited January 21, 2019 by Plus 3 Golfer

[pianewman]

OEM battery 5 years old? Regardless of your liftgate issue, you're WAY beyond borrowed time. Replace it.

That said, our 2013 Cmax liftgate sometimes won't "pull" shut and latch, and requires a gentle push to fully secure the latch. However, the liftgate fully opens/closes every time as designed.

[C-MaxA2]

I have a 2016 (though actually delivered to the dealer in Oct. of 2015) and I plan to replace the battery later this coming summer.  4 years is good enough; no point in pushing the envelope of battery longevity. Especially since it's a sort of 'specialty' battery and not that common. 

[jestevens]

My liftgate motor has enough force that it literally slams the door shut I think. 

 

Replaced the original OEM battery last year with like kind when the car failed to unlock with RF key multiple times in cold weather..had to use the emergency key to get in. 

 

Ford didn't want to replace because their battery tester said it was fine, it's not an inexpensive battery, Motorcraft "extended range" or some crap like that - even with the special they were running at the time I think it cost about $200 including labor at the dealer but no more problems and I wasn't about to try to change it myself outside in 5F weather.

 

So many "modules" in this car and if they don't get proper voltage weird things can start happening.

[plus 3 golfer]

Ford has the MOTORCRAFT® TESTED TOUGH® MAX BATTERIES on sale until the end of January for $129.95 + installation. I believe the Tested Tough is the only one for the C-Max (cheaper one not available). It has a 3 year full replacement warranty and a 100 month prorated warranty. When I had mine replaced in summer 2015, it was on sale for $119.95 + $16 labor + $2 disposal + tax = $148.87 out the door but the :censored: clueless dealer did not reset battery age.

 

It wouldn't suprise me if the dealer charges 1/2 hour labor to reset age which is easily done with ForScan in the time it takes to start car, plug in ELM327 into OBCII port, open ForScan, navigate to the control functions, initiate the age reset function, scan to check PID to make sure it was reset to zero - 5 minutes tops.

Edited January 25, 2019 by Plus 3 Golfer

[markd]

I just replaced mine and the total cost was about $150. In 2014 there was a latch recall OP might want to check and see if their car was serviced.

[stratosurfer]

All,

I had Batteries Plus also test the 12V battery via the terminals in the engine compartment. It tested as REPLACE, I ordered an Oddyssey 67 R and replaced it. However this did not fix my problem. I took back to dealer and they reset the system and I still have the Power Liftgate sticking partway up and or down. The only further troubleshooting I’ve performed was at the recommendation of my mechanic friend asking me if it was better or worse when colder weather. Interestingly, the weather warmed up considerably and it would run, motor staggering nonetheless, all the way up and down. Cold front and now it’s massively stopping. With this data, and hopefully I mentioned that the dealer found no codes thrown which they claim should happen if the power liftgate strut is failing, I am going to replace the left (powered) strut.

Can anyone provide a part number? I can’t find anything online. I find many for Explorers and Edges but nothing for a powered liftgate strut for a 2013 C-Max SEL.

I do recommend an AGM battery for the 12V battery, there are a number of articles discussing 12V flooded lead acid batteries like the hard hits when cranking an engine to keep them from sulfating over time, whereas our C-Maxs start on the traction battery. Also it is a little of a pain to dig out and replace. With the Oddyssey I don’t think I will ever replace the 12v battery again. Hopefully.