C Max Hybrid Backs Up Too Fast

[jchunter]

I have a new 2015 CMax Hybrid with 950 mi.  It simply backs up too fast, especially when first started.  I have to get on the brake immediately to avoid an accident.  Backing out of a parking place is also a problem. 

 

I took it into the dealer and he informed me that the car was within spec and would not change anything.  I pointed out that these incidents were caused by the electric motor turning too fast and could probably be fixed by dropping its minimum voltage slightly.  He said that they didn't know how to do that...

 

What???

 

Does anyone know how lower the minimum electric motor speed?  ( or is there a mechanical adjustment on the accecelerator pedal?)

 

 

 

 

[ptjones]

You don't have your foot on the brake when you backup? Is the ICE running? :)

 

Paul

[DaveofDurham]

You don't have your foot on the brake when you backup? Is the ICE running? :)

 

Paul

 

If the ICE is running when the car is in reverse, isn't the ICE just charging the hybrid battery?  IIRC, the ICE does nothing to propel the car backwards.

[jchunter]

The ICE is typically not running.  Of course my foot is on the brake.  The electric motor is turning too fast.with no foot pressure on the accelerator pedal. 

Edited June 4, 2015 by jchunter

[hybridbear]

Is the back-up behavior different when the car is first started versus other times?

[plus 3 golfer]

I have a new 2015 CMax Hybrid with 950 mi.  It simply backs up too fast, especially when first started.  I have to get on the brake immediately to avoid an accident.  Backing out of a parking place is also a problem. 

 

I took it into the dealer and he informed me that the car was within spec and would not change anything.  I pointed out that these incidents were caused by the electric motor turning too fast and could probably be fixed by dropping its minimum voltage slightly.  He said that they didn't know how to do that...

 

What???

 

Does anyone know how lower the minimum electric motor speed?  ( or is there a mechanical adjustment on the accecelerator pedal?)

IIRC, the following is what I have observed as I also thought when I purchased the car, it seemed to jump off the line in reverse vs drive.  

 

1) The initial torque  when the traction motor is driving the car from a stop is greater in reverse than in drive.  In essence, the cars acceleration when in reverse is greater than when in drive.  So, the cars seems to jump off the line when in reverse with no braking while in drive the cars speeds up slowly. 

 

2) The top speed with no use of  the throttle seems to be around 4.5+- mph from a stop with no braking in both reverse and drive although slight elevation change has a significant affect on the speed.  Again this top speed is reached quickly in reverse and takes longer in drive. My driveway is about 50 feet in length and maybe 2 feet down hill to the street and requires continual use of the brake when backing to the street

 

My guess is that this is intentional as when backing up one normally uses the brake pedal to control speed and not the accelerator.  Whereas in drive one uses the accelerator and brake pedal to control speed.  I would also guess that if Ford decreased the reverse torque, owners would complain that the car backed up too slowly.  When I shift into reverse, my foot is on the brake and I simply ease off the brake to control speed.  So, I don't notice the difference in reverse vs drive now.

 

Also, I doubt Ford wants the dealer changing the operation of the vehicle.  So, Ford likely does not allow such with the OEM diagnostic tool.

[Bill-N]

If the ICE is running when the car is in reverse, isn't the ICE just charging the hybrid battery?  IIRC, the ICE does nothing to propel the car backwards.

 

You're correct.  Reverse is powered only by electricity.  Whether or not the engine is running has no bearing (other than to recharge the HV battery, of course).

[jchunter]

IIRC, the following is what I have observed as I also thought when I purchased the car, it seemed to jump off the line in reverse vs drive.  

 

1) The initial torque  when the traction motor is driving the car from a stop is greater in reverse than in drive.  In essence, the cars acceleration when in reverse is greater than when in drive.  So, the cars seems to jump off the line when in reverse with no braking while in drive the cars speeds up slowly. 

 

2) The top speed with no use of  the throttle seems to be around 4.5+- mph from a stop with no braking in both reverse and drive although slight elevation change has a significant affect on the speed.  Again this top speed is reached quickly in reverse and takes longer in drive. My driveway is about 50 feet in length and maybe 2 feet down hill to the street and requires continual use of the brake when backing to the street

 

My guess is that this is intentional as when backing up one normally uses the brake pedal to control speed and not the accelerator.  Whereas in drive one uses the accelerator and brake pedal to control speed.  I would also guess that if Ford decreased the reverse torque, owners would complain that the car backed up too slowly.  When I shift into reverse, my foot is on the brake and I simply ease off the brake to control speed.  So, I don't notice the difference in reverse vs drive now.

 

Also, I doubt Ford wants the dealer changing the operation of the vehicle.  So, Ford likely does not allow such with the OEM diagnostic tool.

_____________

Thanks for confirming  my suspicions about C Max backup behavior - "jumping off the line" is exactly what I perceive.

 

However, I suspect that the backup speed is controllable with the existing software that deals with all other aspects of backup behavior (e.g., backup camera, sensors, etc.).   I'm betting that the software engineers created a Factory Default Backup Voltage/speed parameter as well as a means of changing it.  You don't just bake numbers like that into the code.  It is essential to be able to control these parameters for testing and qualification, among other things...

 

Therefore I suspect the Ford support personel are just stonewalling or there haven't been enough backup accidents yet.  I'm 75 now and not nearly as quick as I used to be.  Backing out of parking spaces with a car that jumps backwards requires lots of extra care.  IMO, most people use both accelerator pedal and brake while manuvering a car.  Car companies had better tread lightly on existing norms and established behavior. 

 

As for  your guess that customers would complain if Ford fixed the backup problem, I would be happy to send you a dollar for every one who complains about having to press the accelerator pedal to backup faster... ;)

Edited June 5, 2015 by jchunter

[ptjones]

Maybe there is a little difference from car to car, but I don't see this as a problem with my car. You have to have your foot on the brake to get in reverse, you need to have enough pressure so the car doesn't move and then slowly let the pressure off. I'm 68. ;)

 

Paul

[plus 3 golfer]

Maybe there is a little difference from car to car, but I don't see this as a problem with my car. You have to have your foot on the brake to get in reverse, you need to have enough pressure so the car doesn't move and then slowly let the pressure off. I'm 68. ;)

 

Paul

I agree that it's not a problem with my car either.  In fact on my CVT Nissan, if I pull into a steeper downhill parking spot, I have to press the acceleration to start the backup.  I don't have to do that in my C-Max.

 

...

Therefore I suspect the Ford support personel are just stonewalling or there haven't been enough backup accidents yet.  I'm 75 now and not nearly as quick as I used to be.  Backing out of parking spaces with a car that jumps backwards requires lots of extra care.  IMO, most people use both accelerator pedal and brake while manuvering a car.  Car companies had better tread lightly on existing norms and established behavior. 

 

As for  your guess that customers would complain if Ford fixed the backup problem, I would be happy to send you a dollar for every one who complains about having to press the accelerator pedal to backup faster... ;)

Is there really a problem to fix? :)  ;)  Like Paul says ones foot is already on the brake to engage reverse. So for me it very easy to control the backup speed.  If Ford tuned down the reverse torque so that the driver had to use the accelerator pedal to normally back up, my guess is there would be more backup incidents as people would "mix up" the brake pedal and accelerator  - the perceived "unintended acceleration syndrome" where the driver cannot react fast enough to move his right foot from accelerator to brake and can often hit the accelerator again in panic.

[Kelleytoons]

Yeah, I'm old too and I don't even notice any difference in speed between this and my (hugely heavy) Durango, which has so much inertia that it takes a lot to get it going in ANY direction.

 

But that does make me wonder if perhaps the OP's problem is not that the backup speed is too fast but his brakes aren't adjusted properly.  As everyone says, you need to use the brake to go in reverse and control that speed, but perhaps his brakes are "catching" too much (brakes are easy to adjust, at least with old technology.  Who knows what is in cars nowadays?).

 

Or, to put it another way, Maximis certainly does not "jump" in reverse or I'd be in big trouble -- I have a very tight two car (yeah, right -- 1 1/2 is more like it) garage where I am pulled over to the max in order to give my wife enough room to get into the Durango.  I have to manuever *very* carefully backing out or I'd take off the driver's side mirror (I don't pull straight in but rather at an angle to give her that room).  So for me it's a matter of backing out at least five seconds to go the 20 or so feet.  Any issues in backing out would be apparent right away, and I've never even paid it any attention.  So there is something certainly odd here -- perhaps his car just isn't working correctly.

[wab]

I tested ours yesterday.
 
Level street, foot on brake
Put car in reverse, take foot off brake
Car slowly moved (not going to call it accelerated) to maybe 2.5 MPH.
Speedometer didn't move till speed was approaching 2.5. Took about 20' to reach 2.5.
 
I suspect jchunter has a bad module and or corrupted software.
 
jchunter you might want to get our Ford service rep involved.
http://fordcmaxhybridforum.com/user/1579-fordservice/

[plus 3 golfer]

I tested mine this morning and recorded speed vs time in forward and reverse several times with torque pro.  The charts showed that speed vs time curve is virtually the same in forward and reverse although it seems faster in reverse.  I did not measure distance but guess that after 100 feet or so the speed reached 4.5 mph.   The acceleration based on the recorded data from zero to 4.5 mph appeared the same in both forward and reverse.

 

Again, although it feels like the acceleration is greater in reverse than forward, the graphs indicate it's the same.  So, my perception of the acceleration and speed in reverse compared to forward when I first got the car was likely incorrect.

 

So jchunter, if you believe there is a problem and the dealer says there is not, I'd suggest getting an App for a portable device such as a smartphone, tablet, laptop and record the data and then show Ford the difference between forward and reverse speed /acceleration vs time.  Edit: you will also need a $25 bluetooth or wifi OBDII port adapter depending on the App.  There's threads on such Apps and adapters.

Edited June 6, 2015 by Plus 3 Golfer

[kostby]

Add gravity to the potential factors for sensing "faster" acceleration in reverse.

 

My driveway slopes downhill at about 5 degrees (about 4 feet drop in 40 feet), so yes, my C-MAX (or any other car) SEEMS to back up "faster" going downhill than it does going "uphill" to park the car in the same space. The driveway is short, about 40 feet including sidewalk and apron.

[edward stewart]

Humm... I don't notice a jump when I take my foot of the break on a level surface, but as soon as I put a feather on the gas pedal, it jumps. I've never experienced anything like it in the 13 different varied cars, trucks, box trucks, I've driven in the past. It was a new experience which I have adjusted to and just use the break and take my time. 

 

Now when I've having to back up a slope, there is not enough torqe to get me to back up, so I have to press the gas, and it jumps each and every time. I now have 10k under my belt on this car, which I love, but I would love to see a smother motion  for reverse in this car when I do have to press the gas pedal. 

 

Hope my experience helps. 

 

(76 Ford Country Square Station Wagon loved and hated it, 80 Olds Cutlas Supreme, 87 Pon. Grand, Pri, 89 Cad. Eld, 2001 Impala, where my personal, vs... loan cars... 85 Chevy Silvarado 4x4, 83 Buick Riviara, 96 Olds Avira, 2001 Dodge 1500, 96 GMC Small Pickup of some type..., 2013 Ford 150, 2014 Ford Escape Eco, and my personal favorite, vs, 199xxxx International Box Trucks with those push button transmission box trucks which I had to move around in the yard.)

 

Please Ford, come up with a fix. 

[Red]

To add to the list of experiences:

 

I did an initial test drive of a 2015 SE Cmax at one dealership that seemed to 'jump off the line', and the brakes were very 'grabby'. I felt like I had to be very careful while driving  -- but the benefit was that it felt nice and fast when merging on the highway.

 

I later test-drove the car I ultimately purchased (a different 2015 SE Cmax at a different dealership) which seemed to provide a more 'normal' driving experience, and it reacted more gently both to the brakes and the accelerator.

 

I'm not sure if there are differences in the Cmax's sensitivity across different cars (or if I accidentally drove the first car in low gear??)... but putting this out there in case it is helpful.

 

I did read this thread before purchasing, and it encouraged me to do a test at the dealership of the car we were about to purchase: I stepped on the gas while going in reverse, and this did NOT result in any 'jump' or sudden acceleration. My Cmax seems to reverse gently.

 

Thank you for this thread so that I did think to test this. I back out of my driveway every morning into a busy road, and it would have been a dealbreaker if the car behaved as the OP describes.  Our Cmax reverses very smoothly on level surfaces when using the accelerator pedal. So, I'm going to say that what you are experiencing is not how it behaves in all Cmax's. Good luck with getting a fix.

Edited August 18, 2015 by Red