Park brake question
#21
11-18-2016, 02:08 PM
#22
11-18-2016, 04:33 PM
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Location: Adelaide, South Australia
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Same here, Oct 2014 build (MY 2015) V6 S coupe, Aust. delivered Jan 2015.
#23
11-18-2016, 06:54 PM
Veteran Member
My UK 2015MY R with CCM brakes does apply the park brake automatically. I had a play with it this evening and managed to document the behaviour on mine.
(Now my neighbours think I'm a dick for starting and stopping my F-Type half a dozen times at 9pm. Even snatching it into D quickly still lets out a little roar!
)
With the transmission moved into P with foot on brake pedal it does not apply the EPB immediately. I can flick back and forth between a driving gear and P without any activation (I moved back and forth on my drive so there was some actual movement but it made no difference). However if I turn off the ignition in P and then exit and lock the car I can hear the park brake motors activate about two seconds later and when unlocking the (P) symbol is illuminated on the cluster. I can apply and disengage the park brake without ignition as long as the brake pedal is pressed. If I disengage the pakr brake with the ignition already off it appears to stay off even after locking and re-entering the car.
That is different to my 2010MY XJ which applies the EPB when the ignition is switched off unless N is selected (I can feel the brake pedal move as the calipers are moved).
I recall on the X350 it was possible to program the EPB module to disable or enable the auto engage. I expect the modules in the F-Type are also programable. Looking at the fitted parts the early cars (2014MY) used the exact same modules as the X351, which may explain why some of the earlier models have the same behaviour as the XJs. (I was surprised it used the same module as the F-Type use electric motors on each caliper and the XJ uses a single motor and tensioned cables.) The JLR document I quoted on the previous page was dated 2014 which also fits. The part then changed with the 2015MY to a new model-specific part, which was superseeded from K22185. All brake spec variants have the same modules within each VIN range.
So far from this thread (ordered by model year):
Does not auto-apply on selecting P:
DJS's 2014 V6S US
Dogbreath's 2014 V8S US
DPelletier's 2014 V8S Canada
OzXFR's 2014 V6S Oz
Tel's 2016 V8R UK
Does auto-apply:
(My friend's) 2014 V6 UK
Xdave's 2015 V8R UK
Unhingd's 2016 V6S US
Van1's 2017 US
The 2014's should all have the same XJ EPB module with the same software, which spans both does and doesn't auto-apply, which does suggest option programming is the controlling factor and not the hardware.
Interestingly it also spans the US/ROW region divide so it does not appear to be a regulatory thing.
(Now my neighbours think I'm a dick for starting and stopping my F-Type half a dozen times at 9pm. Even snatching it into D quickly still lets out a little roar!
)With the transmission moved into P with foot on brake pedal it does not apply the EPB immediately. I can flick back and forth between a driving gear and P without any activation (I moved back and forth on my drive so there was some actual movement but it made no difference). However if I turn off the ignition in P and then exit and lock the car I can hear the park brake motors activate about two seconds later and when unlocking the (P) symbol is illuminated on the cluster. I can apply and disengage the park brake without ignition as long as the brake pedal is pressed. If I disengage the pakr brake with the ignition already off it appears to stay off even after locking and re-entering the car.
That is different to my 2010MY XJ which applies the EPB when the ignition is switched off unless N is selected (I can feel the brake pedal move as the calipers are moved).
I recall on the X350 it was possible to program the EPB module to disable or enable the auto engage. I expect the modules in the F-Type are also programable. Looking at the fitted parts the early cars (2014MY) used the exact same modules as the X351, which may explain why some of the earlier models have the same behaviour as the XJs. (I was surprised it used the same module as the F-Type use electric motors on each caliper and the XJ uses a single motor and tensioned cables.) The JLR document I quoted on the previous page was dated 2014 which also fits. The part then changed with the 2015MY to a new model-specific part, which was superseeded from K22185. All brake spec variants have the same modules within each VIN range.
So far from this thread (ordered by model year):
Does not auto-apply on selecting P:
DJS's 2014 V6S US
Dogbreath's 2014 V8S US
DPelletier's 2014 V8S Canada
OzXFR's 2014 V6S Oz
Tel's 2016 V8R UK
Does auto-apply:
(My friend's) 2014 V6 UK
Xdave's 2015 V8R UK
Unhingd's 2016 V6S US
Van1's 2017 US
The 2014's should all have the same XJ EPB module with the same software, which spans both does and doesn't auto-apply, which does suggest option programming is the controlling factor and not the hardware.
Interestingly it also spans the US/ROW region divide so it does not appear to be a regulatory thing.
#24
11-19-2016, 08:31 AM
Veteran Member
#27
11-20-2016, 07:47 PM
Senior Member
Same for me. There is a very clear difference between park and no EPB and EPB plus park, this is also the same for my Land Rover. It does automatically release on both when you put it in gear and accelerate.
#28
11-22-2016, 10:51 AM
Veteran Member
I've scared myself significantly, and when I've had my dog, who seems interested in standing near the shifter and hitting ice mode vs dynamic mode constantly.... I sort of wonder at what speed could you apply the parking break?
If I was going at a breakneck speed, and lifted it.... would it apply? That scares/spooks me. Ostensibly, if I was being stupid and forgetful and letting my mind wander, you could pull the top at 29-30mph, and accidentally hit the break? I guess that would be my Darwin award.
#29
11-22-2016, 10:56 AM
Veteran Member
If you pull it up and hold it while at speed, it will bring you to a smooth stop. I haven't been willing to test that.
Dynamic Apply
While the vehicle is moving, the Dynamic Apply mode
provides emergency braking. At a vehicle speed greater
than 2 mph (3 km/h), pulling up and holding the EPB
switch produces a gradual deceleration of the vehicle.
The Red EPB warning indicator illuminates, accompanied
by a warning in the message center and a warning
chime. The vehicle stop lamps also illuminate, activated
by a CAN bus message from the EPB module to
the CJB. Dynamic Apply operation is cancelled if the
EPB switch is either released or pressed down to the
release position, or the accelerator pedal is pressed.
There are four modes of Dynamic Apply, which the
EPB module uses in the following order of preference:
• Electronic Controlled Deceleration (ECD)
• Rear Wheel Unlocker (RWU)
• Dynamic Standstill Detection (DSD)
• DSD+
The ECD mode uses hydraulic braking on all four
wheels to decelerate the vehicle. The other three
modes all use the EPB actuators to operate the rear
brakes to decelerate the vehicle.
ECD
The braking operation is controlled by the ABS module,
in response to a request from the EPB module on the
high speed CAN bus. The ABS module monitors the
deceleration rate using the wheel speed sensor signals,
and adjusts the hydraulic pressure to the brakes
as necessary to achieve the required deceleration. All
of the anti-lock control - traction control system brake
modes remain enabled. As the vehicle comes to a halt,
the hydraulic pressure is reduced to zero and the EPB
module applies the electric park brake with the EPB
actuators.
RWU
RWU mode is used if the ABS module cannot operate
the brakes or achieve a minimum deceleration rate,
but still supplies wheel speed signals to the EPB module.
The wheel speed inputs allow the EPB module to
adjust the clamp load on the rear brakes as necessary
to produce maximum deceleration without locking the
wheels. When vehicle speed decreases to 2 mph (3
km/h), the EPB module fully applies the Electric Park
Brake.
DSD
DSD mode is used if the ABS module cannot operate
the brakes or achieve a minimum deceleration rate,
and the EPB module has no valid wheel speed signals.
In the DSD mode, the EPB module uses the G sensor
to monitor deceleration. To maintain vehicle stability,
the EPB module initially applies a low clamp load to the
brakes, then increases the clamp load in steps. When
the G sensor signal indicates the vehicle has stopped,
the EPB module fully applies the Electric Park Brake.
DSD+
The DSD+ mode is used if the ABS module cannot
operate the brakes or achieve a minimum deceleration
rate, the EPB module has no valid wheel speed signals
and the G sensor has failed. In the DSD+ mode, the
EPB module applies a clamp load calculated to give a
steady rate of deceleration without locking the wheels.
Dynamic Apply
While the vehicle is moving, the Dynamic Apply mode
provides emergency braking. At a vehicle speed greater
than 2 mph (3 km/h), pulling up and holding the EPB
switch produces a gradual deceleration of the vehicle.
The Red EPB warning indicator illuminates, accompanied
by a warning in the message center and a warning
chime. The vehicle stop lamps also illuminate, activated
by a CAN bus message from the EPB module to
the CJB. Dynamic Apply operation is cancelled if the
EPB switch is either released or pressed down to the
release position, or the accelerator pedal is pressed.
There are four modes of Dynamic Apply, which the
EPB module uses in the following order of preference:
• Electronic Controlled Deceleration (ECD)
• Rear Wheel Unlocker (RWU)
• Dynamic Standstill Detection (DSD)
• DSD+
The ECD mode uses hydraulic braking on all four
wheels to decelerate the vehicle. The other three
modes all use the EPB actuators to operate the rear
brakes to decelerate the vehicle.
ECD
The braking operation is controlled by the ABS module,
in response to a request from the EPB module on the
high speed CAN bus. The ABS module monitors the
deceleration rate using the wheel speed sensor signals,
and adjusts the hydraulic pressure to the brakes
as necessary to achieve the required deceleration. All
of the anti-lock control - traction control system brake
modes remain enabled. As the vehicle comes to a halt,
the hydraulic pressure is reduced to zero and the EPB
module applies the electric park brake with the EPB
actuators.
RWU
RWU mode is used if the ABS module cannot operate
the brakes or achieve a minimum deceleration rate,
but still supplies wheel speed signals to the EPB module.
The wheel speed inputs allow the EPB module to
adjust the clamp load on the rear brakes as necessary
to produce maximum deceleration without locking the
wheels. When vehicle speed decreases to 2 mph (3
km/h), the EPB module fully applies the Electric Park
Brake.
DSD
DSD mode is used if the ABS module cannot operate
the brakes or achieve a minimum deceleration rate,
and the EPB module has no valid wheel speed signals.
In the DSD mode, the EPB module uses the G sensor
to monitor deceleration. To maintain vehicle stability,
the EPB module initially applies a low clamp load to the
brakes, then increases the clamp load in steps. When
the G sensor signal indicates the vehicle has stopped,
the EPB module fully applies the Electric Park Brake.
DSD+
The DSD+ mode is used if the ABS module cannot
operate the brakes or achieve a minimum deceleration
rate, the EPB module has no valid wheel speed signals
and the G sensor has failed. In the DSD+ mode, the
EPB module applies a clamp load calculated to give a
steady rate of deceleration without locking the wheels.
#30
11-22-2016, 10:58 AM
Veteran Member
If you just accidentally pull the switch while driving then it will beep and flash a warning up, but won't actually apply the park brake. To intentionally apply it while the car is moving then you need to hold it up for a few seconds and then you will feel it engage and the car will brake quite sharply as you'd expect.
I don't recall if the warning beeps continue, but the red (P) symbol will illuminate to tell you it is applied and it stops quite quickly. I have been told that only 1 second of application is needed to get from 90mph to 70mph should you spot a police car in your rear view mirror and not want to flash up your brake lights. I've never had call to use it at town speeds but I would be surprised if it didn't bring you to a complete stop within 3 seconds (CCM brakes, but at those speeds it probably doesn't make a whole lot of difference).
Your dog operating the mode switch made me laugh.
I don't recall if the warning beeps continue, but the red (P) symbol will illuminate to tell you it is applied and it stops quite quickly. I have been told that only 1 second of application is needed to get from 90mph to 70mph should you spot a police car in your rear view mirror and not want to flash up your brake lights. I've never had call to use it at town speeds but I would be surprised if it didn't bring you to a complete stop within 3 seconds (CCM brakes, but at those speeds it probably doesn't make a whole lot of difference).
Your dog operating the mode switch made me laugh.
Last edited by xdave; 11-22-2016 at 11:01 AM.
#31
11-22-2016, 11:14 AM
Veteran Member
I have tested it. No drama whatsoever. It just feels like the brake has been gently applied for slow but very certain deceleration. Certainly comforting to know it's there in the event of a brake line rupture.
#32
11-23-2016, 01:18 PM
Veteran Member
Dave