Since purchasing my 08 Mariner Hybrid (April 2008) I have not been able to start my car due to dead battery 4 seperate times. Dealer Replaced the battery after the second time. The third time I was on vacation some 1200 miles from home, it was about 8 PM in the evening, and I got a jump start - using jumper cables hooked up to another car. I then drove the car about 40 minutes and parked it for the night. The next moring a local Ford Dealer tested it and found the battery good and the charging system producing accurrate amperage (13.4 volts - I think ??). To be safe for my long trek home, I went to a NAPA Auto parts and bought a "Jump Start" Battery. Last night after work, I found my car again with a dead battery. I used the "Jump Start" battery and was on my way - 40 minute drive. This morning - car started fine.

I have many times noticed that the car while parked will by running something which I think is "pressurizing the regenerative brakes". At least that was what another Hybrid owner told me when the car did it just after unlocking it to get in. It always (mostly??) does this when I go to get in the car.

My question: Should this "pressurizing the brakes" run repetively while the car sits locked and idle??? It is not uncommon for me to hear it cycle 6-8 times during the day working in my yard on a Saturday. Any thoughts/Insights realy appreciated.

 

This doesn't sound normal, mine only does the brake pressure cycling when the door is unlocked after being parked for a while. Also does your vehicle's self jump-start feature using the 330v traction battery also fail? That could indicate you have a larger issue at hand if the big battery is dead after less than a few days parked. I'm sure techs would also want to know if you have any aftermarket electronics installed ( tv, radio, alarms, remote start, etc) that could be causing a problem.

 

Amperage is in amps not voltage. Running, the voltage should be around 14.8V, no higher than 15.2V.

You need a parasitic drain test to determine if there is something draining your battery while sitting. If it doesn't do it all the time, it might be hard to find.

 

My 2008 will pressurize the brake accumulator whenever the car has been sitting for some time and I do something to indicate I'm about to interact with the vehicle (unlock door if locked, open door if unlocked, press brake pedal if already in vehicle but haven't moved in a while (catnap), etc.). I've never timed it but the system will depressurize after the vehicle has been sitting idle (key off: no lock, door or pedal interactions).

If you are hearing your system pressurized/depressurized without some type of wake-up call from user input, then I suspect you have a problem. I would try to seek out a hybrid tech at a Ford dealership and see what they have to say. I don't think what you're describing is normal behavior.

 

I agree with Chris, you have a problem. Do you get a door ajar light, dome light coming On that sort of thing when your driving? I think your FEH might have a bad door switch that's going bad.

GaryG

 

My scangauge(s) don't always turn off. They take more power than you might guess. Especially with the backlight on.

The Scangauge has drained my 12v battery at least a few times.
If I park for longer than a few days ( like I know I'm going out of town ) I unplug my scan gauges, cell phone chargers, basically everything.

A low watt drain, over many days, is the same as leaving your headlamps on for an hour.

Your brakes should NOT repressure without user input, but pressing the key-fob accidently in your pocket or purse will do it.

 

I have this same exact problem... I'm hoping someone can solve it.

 

Well, I took my car back to my Lincoln/Mercury Dealer to have them attempt to find the problem. No luck. I explained that at times on a Saturday while in the yard I can hear my brakes re-pressurizing (and do not have keys on me) They kept in the shop for several hours and never heard it cycle. They found no problem codes and charging system and battery was fine. Official Response "Could not Re-Create" ptoblem.

I have never seen a door ajar light or any indication with a door switch being a problem. Since my scan gauge is conveniently directly in front of my steering wheel (lower left on dash "shelf" - I have decided to unplug every time I shut the car off - in case that is introducing some anomoly. I have also decided to leave in my "4wd" fuse in - to be sure that has not introduced any issue. I did return that before I brought the car in for service. Thank you all for you your helpful suggestions. I'll post an update if I discover anything.

 

Do you have an after market radio? I do... the dealer told me that the radio could stop the modules from sleeping. They said to try pulling the radio fuses overnight before I bring it in. Maybe the scanguage is stopping the modules from going to sleep... I'm going to try the radio thing this weekend and if that doesn't work then I'll bring the car in to them next week.

 

I disabled my radio and am still having the problem...