Recurrence of battery failure

[salman]

Yes, there was a TSB about updating the charging routine software to charge more thoroughly. That TSB was from winter 2013, or maybe spring 2013. To the best of my knowledge no dead 12 volt problems were solved by this TSB.

 

The story with the infotainment screen is similar. One of the early TSBs addressed this, but it turned out not to solve anyone's dead 12 volt problem, to the best of my knowledge.

 

FWIW, I've tried to track this issue closely because my first CMAX, purchased in December 2012, started having dead 12 volts days after purchase. I initiated a buy back request in October 2013 and got a new 2014 in March 2014, when a new model identical to my 2013 became available. Then had two dead 12 volt episodes on the 2014.

 

If you know of a case in which the problem was solved by the charge routine update and/or the infotainment update, please post details.

 

 

RobMax, sorry for the delay here, I've been away from the forum for a few days.  I have one of these devices plugged into the 12v socket in the trunk compartment (the one that never powers off).  It gives a constant readout of the current state of charge of the battery.  The current draw from that device is on the order of a couple milliamps (yes, I've tested it), so it won't drain the battery.

 

Since we have people on here telling people they're wrong and insulting them, essentially telling them that they aren't capable of understand what's wrong ...  (ahem) ... I'm going to attempt to explain things.

 

 

 

--

 

salman - I'm not entirely certain about your statement about the problems not being due to the charging routine or the batteries.  One of the updates performed on my C-Max was a software update to the DC-to-DC converter - the module that charges the 12v battery from the 120v battery.  I also noticed that the last time I had my car jumped, the car clearly extensively charged the 12v battery (you could see the added load on the 120v system on the dash gauges), and then for several days the "resting" state of charge was around 12.9/13.0v - but several days later it fell back to 12.5v.  So I'm wondering if perhaps there's a problem in the way that the car is charging the battery, or the state of charge that it maintains, which is causing batteries to fail.  Just speculation, who knows.

 

In my opinion, based on everything I've read on the forums, there are many different underlying problems for this issue.  One was the SE's radios not turning off.  Another was the water intrusion.  Another was addressed in that software update as a part of the recall.  And there are others I'm not recalling.  And there's still at least one (or more) cause that remains unknown, which Ford Engineering has stated somewhat publicly that they're still working on a solution for.

 

For some people, replacing the battery from the bad batch that Ford got solved the problem.  For others, replacing the radio solved the problem.  For others, replacing the fuel pump or wiring harness where water intrusion / corrosion was occurring solved the problem.  But for an unlucky few of us, the problem remains.

 

 

[salman]

traveler

 

you might have them check the BCM module for proper connection, esp the ground connection

[CMax-Traveler]

If you know of a case in which the problem was solved by the charge routine update and/or the infotainment update, please post details.

 

I'm not aware of any cases where the DC-to-DC converter software update solved things.  If I remember correctly, the DC-to-DC software update TSB (13-5-1 and 13-6-23) was initially targeted at resolving a cold weather problem, where the 12v wasn't receiving sufficient charge in cold (below freezing) weather when being run for short periods of time at high electrical load.  I think they may have eventually updated the TSB to apply to all temperature conditions, not just cold weather.

 

My question was more whether or not a problem still remains there.  The DC-to-DC converter plays the role of alternator in the C-Max, so it's unique to hybrids.  Because we don't have a starting load requirement, they're smaller batteries than most cars.  Under regular use, from my voltmeter monitoring, the DC-to-DC converter seems to maintain a SoC around 70-80% -- which, over time, will result in sulfation (and thus, failure) of the battery.

 

In my car, I've had two problems.  One, a good battery ends up drained for no reason overnight - likely a module turning on and staying on, thus draining the battery.  So, that problem is still out there.

 

But the other problem is I've had two 12v batteries go bad and need to be replaced.  And it seems a LOT of C-Max 12v batteries have gone bad.  It has been blamed on a bad batch of batteries - but so many, produced over such a long timeframe?  I'd be more inclined to say it's the C-Max causing them to go bad b/c of maintaining an insufficient state of charge.  Now, disclaimer: that's just speculation; I'm not an engineer; I don't know that much about car batteries, and I don't have any direct evidence to back that up... so I'm just fueling Internet rumors here.  But it seems to me to be a better explanation for so many bad batteries than I've seen anyone else come up with.  I'm not sure how to test that, though, besides going through and examining all of those dead 12v batteries - which I hope Ford is doing. So... thoughts?

 

you might have them check the BCM module for proper connection, esp the ground connection

 

They checked that the last time it was in; it appeared to be fine.

[salman]

News to me that a lot of batteries have been bad. I don't think I've heard that before, except as speculation about the cause of the dead 12 volt syndrome in November 2012 through February 2013. That was proven not to be the case, so far as I can tell.

 

It is true that many cars suffering dead 12 volt syndrome have had their batteries changed. That was done for two reasons: first, in the early days, as a blind shot at solving the problem, and second because a battery's ability to take a full charge is diminished when it is run down to a very low charge. The batteries were not changed because of a bad batch of batteries.

 

Bad connections (on the BCM or any electrical connector) can cause a system to activate or stay active when it is supposed to be off.That seems to be the one thing that has been a successful repair so far. Two caveats: 1) so far. Only more time will tell if this has been a real fix, and 2) it can't be a repair until the bad connection is found, and in your case it seems it has not yet been found.

 

Third caveat: yes, in your case it could turn out to be a problem with something other than a connector. If that is ever verified and repaired, please let us all know, for it would be new information.

Edited August 30, 2014 by salman

[drdiesel1]

Here's the method I followed for testing for a parasitic load:

1) Open the rear liftgate, close all the doors, lock the car, then manually latch the rear liftgate by closing the lock mechanism with a screwdriver, so that the hazards blink once.  This makes the car *think* it's locked and closed, but gives me access to the rear compartment - the hazards blinking once confirms the car believes it's sealed. In theory, the car should eventually go to sleep on it's own, but I did this just to be certain. **WARNING** For anyone else trying this, be sure to unlatch the liftgate before closing it by pressing the open button, or you could damage your car!!!

2) Remove all of the rear battery covers, to give access to the 12v battery.

3) Clamp a 12v ammeter around the battery ground cable (the thick black one going from the battery to the floor of the car).

4) Wait until the car is asleep - 10 minutes or so.

5) Read the output on the ammeter.  Wait several hours, read again, etc. etc. etc.

 

My results were:

* Unlocking / locking the car generated a draw of 12-16 amps.

* Having the car unlocked and the hatch open there was a draw of around 5-6 amps.

* Having the car locked and all lights off, there is a draw of around 2-2.5 amps while the car is not in sleep mode.

* Once the car goes to sleep, the current draw falls to 0.1A.  Checking it for several hours after it's asleep, I've never managed to witness anything above 0.2A, but unfortunately my ammeter goes to sleep after 15 minutes so I can't monitor it continuously via a camera feed or anything like that.

Note: The resolution on my ammeter is 400A +/- 0.1A so we're right at the edge of its capabilities, but regardless, 0.2A shouldn't kill a good battery overnight.

 

 

EDIT: Yes, the load on my car did fall to 0.2A after about 15 minutes, despite being unlocked.  So it does appear to go to sleep regardless, at least in this particular instance.

I see you're using a clamp type amp meter to read parasitic load. Unfortunately, unless it's a Micro ($500 to $700 bucks on average) amp clamp, it's incapable of reading below 500 milliamps. You can read down to 1 M/A with a DVOM setup inline with the battery on the 10 amp scale. Some meters even offer M/A readout, so you don't need to covert it. Most systems top out around 35 M/A. I have come across a few trucks that read 50 M/A's and never cause problems (they have much larger batteries) with starting, even after a few weeks.

 

On smaller systems like the C-Max, my limit would be the 35 M/A threshold. Anything above that will cause battery problems.

If anyone is interested in how to setup a DVOM to read a parasitic draw, I can explain it or even do a short video. If anyone

is interested, just post the request in this thread.

 

The cars systems will go to sleep without locking the car. Some modules can take as long as 40 min. to sleep.

They never shut off, so there is a voltage draw from every module to retain memory. It's called KAM. Keep Alive Memory.

This is what your meter can not read and makes you think there's not a problem with an amperage draw on the system.

I would bet the car has at least a 20 M/A draw all the time after the modules sleep.

Edited August 30, 2014 by drdiesel1

[CMax-Traveler]

I see you're using a clamp type amp meter to read parasitic load. Unfortunately, unless it's a Micro ($500 to $700 bucks on average) amp clamp, it's incapable of reading below 500 milliamps. You can read down to 1 M/A with a DVOM setup inline with the battery on the 10 amp scale. Some meters even offer M/A readout, so you don't need to covert it. Most systems top out around 35 M/A. I have come across a few trucks that read 50 M/A's and never cause problems (they have much larger batteries) with starting, even after a few weeks.

 

On smaller systems like the C-Max, my limit would be the 35 M/A threshold. Anything above that will cause battery problems.

If anyone is interested in how to setup a DVOM to read a parasitic draw, I can explain it or even do a short video. If anyone

is interested, just post the request in this thread.

 

The cars systems will go to sleep without locking the car. Some modules can take as long as 40 min. to sleep.

They never shut off, so there is a voltage draw from every module to retain memory. It's called KAM. Keep Alive Memory.

This is what your meter can not read and makes you think there's not a problem with an amperage draw on the system.

I would bet the car has at least a 20 M/A draw all the time after the modules sleep.

 

As I mentioned in my post, my meter has a specified resolution of 400A +/- 0.1A - so in theory it can measure down to 100 milliamps.  In practice, I'd say I can distinguish between 200milliamps and zero, but probably not less.

 

When my car is fully "asleep" the meter reads 0.1 or 0.2 amps.  Which is around the smallest load it can detect, but it's definitely negligible.

 

The 12v battery in the C-Max is rated at 40Ah.  Which means that with the smallest load detectable by my meter, the battery should not discharge fully for over 200 hours.  Even if we say my meter can't accurately measure less than a full amp, that's still 40 hours.  In my personal experience, my 12v battery discharged in less than 9 hours.  That would indicate either a battery that cannot hold a charge (but it passed all tests at the dealer), an undercharged battery (but it indicated ~80% charge at 1am prior to the discharged condition at 10am), or a parasitic load of at least 3-4 amps.  Which would be easily detectable by a non-Micro meter.

 

So, my meter can detect a parasitic load that would be required to drain the car in the observed duration, and I have not witnessed any load of that magnitude.

[Kelleytoons]

Don't shoot the messenger, but it seems to me that if any of these problems that folks here have concluded are the "cause" of their battery issues were true, then ALL (or at least most) of us would also have them.  IOW, if there is a fundamental design flaw somewhere, it wouldn't be so isolated (and thus easier to fix).

 

That would lead me to believe it IS a bad battery or other "bad" critical part that sometimes is made incorrectly or installed incorrectly, or manufactured incorrectly, but most of the time is not.  Which is why most people do not have these issues.  Even though most of us here are not engineers, we have to at least stipulate that Ford's engineers (or at least some of them) are competent, and would otherwise have solved this issue long before now.

 

I don't know how cars are made (not my field) but in computers and other tech equipment parts are often outsourced from a variety of places, which is why you can get a bad batch of, say, screens that affect certain cell phones, while other phones (the exact same models) are just fine.  Again, if the problem was such that the design was flawed then we would expect ALL of the phones or the vast majority of them not to work.

 

Anyway, just my two cents (and now I'll pull my head back into my shell).

[CMax-Traveler]

It is true that many cars suffering dead 12 volt syndrome have had their batteries changed. That was done for two reasons: first, in the early days, as a blind shot at solving the problem, and second because a battery's ability to take a full charge is diminished when it is run down to a very low charge. The batteries were not changed because of a bad batch of batteries.

 

My dealer told me: Many many C-Max 12v batteries were replaced that were not bad, just because they had discharged.  As a result, Ford instituted a policy that the batteries must be tested thoroughly and fail before a replacement would be approved.  But even after that, a large (but smaller) number of 12v batteries still tested as failed and needed to be replaced.  As for the underlying cause as to why they've tested bad, I have no idea.  Bad batch?  Unlikely.  Discharged too often?  Perhaps.  Something else?  ??  Realistically, only Ford can know this by testing the failed batteries.

 

Don't shoot the messenger, but it seems to me that if any of these problems that folks here have concluded are the "cause" of their battery issues were true, then ALL (or at least most) of us would also have them.  IOW, if there is a fundamental design flaw somewhere, it wouldn't be so isolated (and thus easier to fix).

 

That would lead me to believe it IS a bad battery or other "bad" critical part that sometimes is made incorrectly or installed incorrectly, or manufactured incorrectly, but most of the time is not.  Which is why most people do not have these issues.  Even though most of us here are not engineers, we have to at least stipulate that Ford's engineers (or at least some of them) are competent, and would otherwise have solved this issue long before now.

 

Yep, that's 100% accurate - many of the problems that people have concluded are the problem should mean everyone would have the problem.  But there are many other factors that could contribute: the way the car is driven, the frequency and duration of trips, whether it sits unused a lot, the environmental conditions, manufacturing differences in the cars, bad batch of radios, etc. ... and whatever those factors are trigger a specific set of circumstances causing the various types of problems people have encountered, and causing the vast majority of owners to have no problems at all.  We're all grasping at straws here, and sadly, it seems at the moment that Ford engineering is as well.

[drdiesel1]

As I mentioned in my post, my meter has a specified resolution of 400A +/- 0.1A - so in theory it can measure down to 100 milliamps.  In practice, I'd say I can distinguish between 200milliamps and zero, but probably not less.

 

When my car is fully "asleep" the meter reads 0.1 or 0.2 amps.  Which is around the smallest load it can detect, but it's definitely negligible.

 

The 12v battery in the C-Max is rated at 40Ah.  Which means that with the smallest load detectable by my meter, the battery should not discharge fully for over 200 hours.  Even if we say my meter can't accurately measure less than a full amp, that's still 40 hours.  In my personal experience, my 12v battery discharged in less than 9 hours.  That would indicate either a battery that cannot hold a charge (but it passed all tests at the dealer), an undercharged battery (but it indicated ~80% charge at 1am prior to the discharged condition at 10am), or a parasitic load of at least 3-4 amps.  Which would be easily detectable by a non-Micro meter.

 

So, my meter can detect a parasitic load that would be required to drain the car in the observed duration, and I have not witnessed any load of that magnitude.

Considering you said the meter shuts off after 15 min. You're unable to monitor long term. This would be key

to finding the high amperage battery killer. Without a way to monitor it long term, you're kinda stuck with not knowing.

 

I've never known of an amp clamp that can read below 500 milliamps, unless it's an expensive micro amp clamp.

Edited August 30, 2014 by drdiesel1

[SnowStorm]

My results were:

* Unlocking / locking the car generated a draw of 12-16 amps.

* Having the car unlocked and the hatch open there was a draw of around 5-6 amps.

* Having the car locked and all lights off, there is a draw of around 2-2.5 amps while the car is not in sleep mode.

* Once the car goes to sleep, the current draw falls to 0.1A.  Checking it for several hours after it's asleep, I've never managed to witness anything above 0.2A, but unfortunately my ammeter goes to sleep after 15 minutes so I can't monitor it continuously via a camera feed or anything like that.

Note: The resolution on my ammeter is 400A +/- 0.1A so we're right at the edge of its capabilities, but regardless, 0.2A shouldn't kill a good battery overnight.

 

 

Rob - in theory, the car should go to sleep after 10 minutes, regardless of whether the doors are open, closed, locked, unlocked, etc.  But since I don't know how it's actually programmed, I'd rather be safe than sorry, for testing purposes.  There have been anecdotes of people having more trouble who leave their cars garaged and unlocked, but there are many others of us who lock it regardless, so I'm not sure it matters.  But, since I'm in a testing mood, I'll test it out now with my ammeter and will report back.

 

EDIT: Yes, the load on my car did fall to 0.2A after about 15 minutes, despite being unlocked.  So it does appear to go to sleep regardless, at least in this particular instance.

Unfortunately, after the car "goes to sleep" it periodically "wakes up" and does stuff (gets a midnight snack, takes the dog out - goodness knows what).   (I think someone said what it does but I don't remember.)  You can see my all night current monitoring results here in post #25.  A half hour after going to sleep the current jumped to 3 amps for 6 seconds.  Then it periodically went to 0.2 amps for 30 seconds.  (My minimum measurement capability was about 20 mA.)  I had hoped to build a current monitor that I could check to make sure the car had "gone to sleep" but with all the insomnia going on I realized that you would have to keep checking all night!  Obviously, if it stuck ON at 3 amps, you could have a dead battery next day.

 

I wonder if a lot of batteries (including mine last winter) tested "bad" because they were being repeatedly discharged excessively but not quite enough to prevent starting the next morning.  So you go along for weeks or months not knowing what is happening until the battery goes low enough to prevent a start.  I wish we new the lowest voltage that would still energize the car.  From my experience I know that 3.5 volts is too low!

[CMax-Traveler]

Considering you said the meter shuts off after 15 min. You're unable to monitor long term. This would be key

to finding the high amperage battery killer. Without a way to monitor it long term, you're kinda stuck with not knowing.

 

I've never known of an amp clamp that can read below 500 milliamps, unless it's an expensive micro amp clamp.

 

No, I can't do long-term monitoring.  But my point was that it's not a constant parasitic load, and a standard parasitic load test won't help.  It's some module that randomly comes on and stays on, and that would require a very extended, nightly, parasitic load test for potentially months until the problem recurs -- and it would require much more patience than any of us have.  And then, once it does happen, good luck figuring out which module it was, since the car will have died and all you have left is a log of the current draw - not what was drawing it -- unless you also come up with a way to be notified on one of those random nights when it happens so you can go and pull fuses until it stops.

 

Unfortunately, after the car "goes to sleep" it periodically "wakes up" and does stuff (gets a midnight snack, takes the dog out - goodness knows what).   (I think someone said what it does but I don't remember.)  You can see my all night current monitoring results here in post #25.  A half hour after going to sleep the current jumped to 3 amps for 6 seconds.  Then it periodically went to 0.2 amps for 30 seconds.  (My minimum measurement capability was about 20 mA.)  I had hoped to build a current monitor that I could check to make sure the car had "gone to sleep" but with all the insomnia going on I realized that you would have to keep checking all night!  Obviously, if it stuck ON at 3 amps, you could have a dead battery next day.

 

I wonder if a lot of batteries (including mine last winter) tested "bad" because they were being repeatedly discharged excessively but not quite enough to prevent starting the next morning.  So you go along for weeks or months not knowing what is happening until the battery goes low enough to prevent a start.  I wish we new the lowest voltage that would still energize the car.  From my experience I know that 3.5 volts is too low!

 

Those results are pretty awesome, but not surprising - things are constantly waking up and going back to sleep, as evidenced by all of the buzzing, whirring, fans, etc. that have been documented.  Some of the things I'm pretty sure it does is opening/closing the grill flaps, cooling the HV battery, maintenance on the fuel system pressure, and others.  I'm assuming Ford has a bunch of C-Max'es with known problems in a lab somewhere with similar test equipment hooked up to try and trace this problem - and if they don't, they should.

 

I know from my experience that 5.7 is too low to energize the car.  But I also know that, in the months I've been monitoring my car, other than the morning that it didn't start, I've never seen the "resting" voltage drop below 12.3v.  So I don't think it's an issue of the charged state gradually falling until it's too low, I'm pretty sure it's a sudden thing - something turns on and gets stuck on that drains it.  I genuinely wish Ford luck in figuring out what, though, for all of our sakes!

[jdbob]

In the document http://www.motorcraftservice.com/vdirs/diagnostics/pdf/OBDSM1402_HEV.pdf some systems have a 12V battery range of 11.0V to 18.0V while others have a range of 6.0V to 19.0V. What does that mean? I have no idea.

[drdiesel1]

No, I can't do long-term monitoring.  But my point was that it's not a constant parasitic load, and a standard parasitic load test won't help.  It's some module that randomly comes on and stays on, and that would require a very extended, nightly, parasitic load test for potentially months until the problem recurs -- and it would require much more patience than any of us have.  And then, once it does happen, good luck figuring out which module it was, since the car will have died and all you have left is a log of the current draw - not what was drawing it -- unless you also come up with a way to be notified on one of those random nights when it happens so you can go and pull fuses until it stops.

 

 

It's a process of elimination and it's never easy, but it can be done with persistence ;)

[SnowStorm]

It's a process of elimination and it's never easy, but it can be done with persistence ;)

So, let's all apply our collective persistence and see what can be done.  Two first steps could be:

1. Connect an alarm to warn us that something is wrong.  It could watch voltage, current or charge.  A charge based alarm would be best followed by voltage and then current.  (I recently purchased a voltage alarm intended for model aircraft and will post details soon.)
2. Determine where the current is going.  This is the hard part.  I'm proposing we list the most likely candidates and devise a low cost way of monitoring each one.  Then when the alarm goes off you go check which item is the culprit.  Of course I'm assuming the battery is drained over a period of hours, not a few minutes!

So let's all create a list of the most likely candidates with the source of our information (personal observation, Ford service data, other online reports, etc).  Here's a start from CMax Travelers post.

1. Opening/closing the grill flaps
2. Cooling the HV battery
3. Maintenance on the fuel system pressure

Please add to it.  We then need someone with wiring diagrams to locate all the fuses or other good monitoring points.  I'm tired of waiting.

[drdiesel1]

So, let's all apply our collective persistence and see what can be done.  Two first steps could be:

1. Connect an alarm to warn us that something is wrong.  It could watch voltage, current or charge.  A charge based alarm would be best followed by voltage and then current.  (I recently purchased a voltage alarm intended for model aircraft and will post details soon.)
2. Determine where the current is going.  This is the hard part.  I'm proposing we list the most likely candidates and devise a low cost way of monitoring each one.  Then when the alarm goes off you go check which item is the culprit.  Of course I'm assuming the battery is drained over a period of hours, not a few minutes!

So let's all create a list of the most likely candidates with the source of our information (personal observation, Ford service data, other online reports, etc).  Here's a start from CMax Travelers post.

1. Opening/closing the grill flaps
2. Cooling the HV battery
3. Maintenance on the fuel system pressure

Please add to it.  We then need someone with wiring diagrams to locate all the fuses or other good monitoring points.  I'm tired of waiting.

This would be a great idea.  I don't own a Hybrid, but maybe I can still add to it.

Your number 3 isn't a function of the car. For a replacement we could add #3 EVAP system leak detection.

 

The number 2 on the list would be a suspected sticking relay for the HVB cooling fan and not necessarily

a control module coming on after the cars been parked. As others have stated, they heard the fan running long

after it should have been turned off. This issue would be a focal point for me and shouldn't be difficult to verify.

 

I find the K.I.S.S. method works best when bug hunting electrical gremlins. "Keep It Simple Stupid" :lol:

Edited August 30, 2014 by drdiesel1

[SnowStorm]

Updating the list - rewording and adding:

1. Grill flap operation
2. HV battery cooling
3. EVAP system leak detection (fuel system)
4. Water pump operation
5. Radio (?)
6. Short circuit in a connector (will need to pick the most likely circuits)

It would help to know the current drawn by each item to help prioritize.  Anything that draws a couple of amps or more is a candidate.  I wish we knew what pulls 3 amps for 6 seconds in the middle of the night.

[salman]

My dealer told me: Many many C-Max 12v batteries were replaced that were not bad, just because they had discharged.  As a result, Ford instituted a policy that the batteries must be tested thoroughly and fail before a replacement would be approved.  But even after that, a large (but smaller) number of 12v batteries still tested as failed and needed to be replaced.  As for the underlying cause as to why they've tested bad, I have no idea.  Bad batch?  Unlikely.  Discharged too often?  Perhaps.  Something else?  ??  Realistically, only Ford can know this by testing the failed batteries.

 

 

Yep, that's 100% accurate - many of the problems that people have concluded are the problem should mean everyone would have the problem.  But there are many other factors that could contribute: the way the car is driven, the frequency and duration of trips, whether it sits unused a lot, the environmental conditions, manufacturing differences in the cars, bad batch of radios, etc. ... and whatever those factors are trigger a specific set of circumstances causing the various types of problems people have encountered, and causing the vast majority of owners to have no problems at all.  We're all grasping at straws here, and sadly, it seems at the moment that Ford engineering is as well.

 

The first comment from your dealer matches what has been reported on the forum and also matches what I have seen: batteries were replaced because they had been discharged, and also as a shot in the dark in early 2013 to try to fix the 12 volt problem.

 

The second comment, which I think you are also attributing to the dealer is about batteries that are testing bad. There just are not many reports on this forum about batteries testing bad. Very few. far fewer than reports of dead 12 volt systems (ie drained batteries). I don't see any evidence in reports on the forum that points to a bad batch of batteries.Ford has not issued a TSB about a problem with the CMax battery, only TSBs that address the charging routines and systems that do not shut down (including the faulty connectors that cause systems to awaken or stay awake).

 

I still see no evidence pointing to a battery problem.

 

There is considerable evidence of problems with bad connectors and bad connections (main harness, coolant pump, gear shifter, & BCM module), and evidence that when these things are identified and fixed the dead 12 volt syndrome seems not to re-occur . . . . although only time will tell if these are full and permanent fixes.

 

There is also lots of evidence that some dealer service departments are better than others.

 

Some service departments dive into the problem, keep abreast of the TSBs, and contact the Ford Tech Hotline to discuss the problem with an engineer.

 

Other service departments say that they see no problem and have never heard of 12 volt problems and they won't look for the problem or contact Ford engineers. Bad departments tell the owner it is their fault for outrageous reasons. . Owners on this forum have been told they don't drive the car enough, that there is a minimum number of miles per day or week that must be driven, and other total BS.

 

My original dealer's service manager knew nothing about hybrids, did not know there was a step down converter, would not call Ford's hot line, and did nothing to try to fix the problem. They even lied to me about changing the battery. In Feb or March 2013 I switched to a different dealer service department and they are great.

Edited August 30, 2014 by salman

[salman]

The long discussion about the practical difficulty of round-the-clock and weeks-long monitoring of intermittent current draws and testing to find the location of the current draw should be enough to explain why this has been a difficult problem for Ford to track down.

 

Also think about the problems that Ford's recent TSBs and SSM's have described: All the problems with electrical connectors are problems that can be visually checked by opening the connectors and seeing if there has been water intrusion. The coolant pump connectors are like, plus the coolant pump can be heard. Ford mechanics have heard the pump running when it should have been off, and they have seen fouled connectors.

 

Tracing an intermittent parasitic draw is not easy, and is especially devilish if the activated component is not obvious in some way.

 

If it was easy, Ford would have figured it out a year ago. There is no doubt they have been working on it. Posts on the forum tell the story of the engineers working to diagnose re-purchased cars and also working on cars out on the road under warranty, Some of the parts being changed under warranty are not cheap.

 

All of this is important for understanding the magnitude of the problem: 1) the 12 volt syndrome makes a non-trivial minority of CMaxs inoperable on a random basis, 2) the problem is not easy to troubleshoot, 3) Ford has made lemon law buy backs on a bunch of 12 volt cases reported here on the forum and mostly done so without a fight.

[Adrian_L]

Beautifully stated Salman.   Thank you. 

[dmk2000]

Hello Everyone.

Last Saturday, I had another reoccurring problem with 12 V battery right after driving it for at least 40 minutes. In my case due to lower voltage of 12 V battery, Transmission shifter relay got stuck and would not allow to be shifted to any gear. Anyways, checked battery voltage, and it was 12.1 V without load. I called Ford Road side assistance, upon arrival of a tow truck, I inform driver that last time ford Dealer told me that it was due to lower voltage on 12 V battery. Driver pulled out BIG and advanced jump pack with a build in tester for alternator and all. After connecting it to the car, and waiting for a few minutes we try to start car, and behold shifter start moving again. After I place gear shifter back in P, and pressed gas pedal to the floor, ICE started. During this time we still had this battery pack connected to the car, and tester showed that this battery pack started charging, and alternator status "PASS". However, when ICE turned off, tester showed that there is no charging occurring on 12 V system. What it tells me is that as of now the only time my 12 V battery will be charged is when ICE is on. Now it makes sense to me. If you are trying to keep CMAX on HVB power as much as possible, and minimize use of ICE, it might not have enough time to properly charge 12 V battery.

This can be a PART of the reason why we have so many issues with 12 V battery. I am not calming that this is a reason, this is just an educated guess, also, when you are starting with not properly charged battery, every parasitic current draw whenever it is small or large, can overtime cause 12 V issues.

As a temporary solution, I am starting maintenance charging 12 V battery on weekly bases. What a pain in the ***. Let put this way, until Ford comes up with proper solution to our 12 V battery issues, I tell everyone that my wife CMAX hybrid is actually plug-in.   

[ptjones]

All these things to monitor the battery or go turn the key at night when you hear it doing something are ridiculous. Not the suggestions, but the fact that you would have to do any of them. :) We love the car. Handling, features, how fast it is if you need it, mileage, everything. Except that our battery has been dead twice now. I can't have a car like that, and we shouldn't have to deal with that... It's not reliable and not safe if my wife needs to take the kids to the hospital or something...

 

"Gee honey, you forgot to wake me at 3 a.m. so I can see if my battery is draining".

 

I agree 100%.  Ridiculous.  Every night, should I disconnect the battery ground strap on my NEW CAR as well??  

 

I can't say enough good things about my C-max, but if my wife gets stranded with her 80 year-old father and our 3 year-old daughter, I'll have more than caustic words for my dealer.

With a Jumper Battery this becomes just annoyance, show your wife how to use it, it will only take a couple of minutes. Then you don't have to worry about it. FORD will fix it eventually and in the mean time you are covered. IMHO :) 

 

Paul

[Zathrus]

During this time we still had this battery pack connected to the car, and tester showed that this battery pack started charging, and alternator status "PASS". However, when ICE turned off, tester showed that there is no charging occurring on 12 V system. What it tells me is that as of now the only time my 12 V battery will be charged is when ICE is on. 

 

With ICE off, the HVB does indeed charge 12V battery via a DC-DC converter (on both hybrid and energi models).

 

You may want to have the dealer check for a charging problem with your vehicle. At the same time, what you observed may have been the result of some wierd interaction between the jumper battery pack and the DC-DC converter.

Edited September 3, 2014 by Zathrus

[plus 3 golfer]

When the car is "ready to drive" whether ICE runs or not, the DC/DC converter is supplying the 12 V load like an alternater does as it puts around 13.8+V on the 12 V system which is above the nominal 12 V battery voltage absent charging  You can see this in Engineering Test Mode.

 

With the push button start:

 

1) Push and hold the "OK" button on the left input pad on the steering wheel

2) DO NOT STEP ON THE BRAKE.  Push the start button while still holding the "OK" button.  

3) Engineering test mode will come up on the left hand screen.  It might be blocked by another message  but you can see the letters ET in the upper left.  Release the "OK" button and push it again to clear the other message.

4)  The Engineering Test Mode screen should be displayed.

5) Push the up or down arrows to scroll through the ETM screens.

6) One screen will show the battery voltage.  If the car is still not ready to drive, the voltage will show 12.X V (mine just showed 12.5 V)

7) Now press the brake pedal and hold it while you press the start push button and "read to drive" should show up.

8) Press 'OK" to clear the ready to drive display and the voltage on the ETM should now show around 13.8 V.

Edited September 3, 2014 by Plus 3 Golfer

[dmk2000]

With ICE off, the HVB does indeed charge 12V battery via a DC-DC converter (on both hybrid and energi models).

 

You may want to have the dealer check for a charging problem with your vehicle. At the same time, what you observed may have been the result of some wierd interaction between the jumper battery pack and the DC-DC converter.

Zathrus and Plus 3 Golfer, you could be right about potential issue with DC-DC converter on my CMAX.

I will test Engineering Test Mode tonight. Will let you know.

Thanks

[dmk2000]

Plus 3 Golfer.

Did a test following your procedure and here are my results.

With car not ready to drive it shows 12,4 Volts.

With car ready to drive with ICE off, it showed 13.7 Volts.

You are correct, HVB does charges 12 V battery. That said, I cannot understand is why after driving for a straight 40 minutes, as soon as trying to park on a driveway transmission got stuck due to low voltage on 12 V battery, we are talking same moment as soon as start/shutdown button was pressed in order to turn car off not after it was left along overnight?. 40 min drive should be enough to charge even depleted battery.

Do you or anyone have any suggestions what could it be.

 

P.S. Same time as I was performing your test, I connected battery charger to see what state battery charge is. According to charger 12 V battery was 80% charged. Not sure if this is good or bad. Three weeks ago, dealer did diagnostic on battery and it passed.