ABS/DSC/Traction control: How it works!
#41
08-14-2013, 07:52 PM
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Not sure if you guys/gals want to know things like this, but I was asked a question in the X350 section. So I thought I would post this response for all to have an idea how these systems work. If this post not in the right place, I am sure Admin will help out and put it in the right place.
Traction control works like this:
The anti-lock brake system (ABS) modulates brake pressure on each wheel independently to maintain vehicle stability during braking. The ABS continually monitors the rotational velocity of each wheel anytime the ignition switch is in the run position and determines if a tire is skidding when the brakes are applied. Only then does the ABS intervene to modulate the brake pressure to the skidding wheel. The modulation continues until the wheel rotates freely. The brake pressure is then restored and the modulate/restore cycle is repeated whenever skidding is detected. This cycle occurs at a rate of several times per second.
The ABS module is capable of detecting the following system conditions:
[ul][*]hydraulic valve failure[*]wheel speed sensor failure[*]ABS power relay short circuit[*]interconnect failures to the ABS sensors, power and ground to the ABS module[*]over/under voltage conditions [/ul]The ABS provides self-diagnostics and displays failure messages via the ABS indicator in the instrument cluster. Failure of the ABS module, for whatever reason, will not compromise the normal operation of the brake system.
The Dynamic Stability Control (DSC) system includes the:
[ul][*]anti-lock brake system.[*]yaw/lateral control.[*]full speed traction control. [/ul]The DSC system manages the braking system to enhance the driver control of the vehicle.
The DSC system continually monitors the steering wheel angle, master cylinder brake pressure, front and rear wheel speeds, vehicle yaw and lateral rate acceleration.
The yaw/lateral rate sensor supplies a signal to the DSC module, via a serial link, which monitors the vehicles rate of acceleration from its central axis in a sideways direction, and also the vehicles angular rotation around it's central axis.
The driver input parameters are continually monitored via the brake master cylinder dynamic stability control sensor, the brake pedal travel sensor and the steering wheel angle sensor.
DSC is enabled/disabled via the traction control ON/OFF switch.
Self-diagnosis of the DSC system is provided via the instrument cluster message centre.
Traction control is an additional function added to the ABS/DSC system. The vehicles driven wheels are continually monitored for wheel spin relative to the calculated reference speed and to each other. If wheel spin is detected, the traction control function intervenes independently of the driver, applying brake pressure to the slipping wheel and reducing the engine drive torque supply. Meanwhile, brake pressure is modulated by the traction control until traction is re-established. Traction control brake actuation is diminished above 40 km/h (25 mph). Above this speed traction control relies primarily on engine torque reduction.
Traction control is enabled/disabled via the traction control ON/OFF switch. When the switch is in the (OFF) position, the amber traction control warning lamp solidly illuminates within the instrument cluster message centre. The traction control is automatically activated when the ignition is switched on. Self-diagnosis of the traction control system is also provided via the instrument cluster message centre.
The traction control brake intervention is automatically disabled whenever the brakes exceed a temperature limit. The traction brake intervention will remain disabled until the brakes have cooled, irrespective of ignition switch position or ignition switch cycling.
[sm=wtf.gif]
Traction control works like this:
The anti-lock brake system (ABS) modulates brake pressure on each wheel independently to maintain vehicle stability during braking. The ABS continually monitors the rotational velocity of each wheel anytime the ignition switch is in the run position and determines if a tire is skidding when the brakes are applied. Only then does the ABS intervene to modulate the brake pressure to the skidding wheel. The modulation continues until the wheel rotates freely. The brake pressure is then restored and the modulate/restore cycle is repeated whenever skidding is detected. This cycle occurs at a rate of several times per second.
The ABS module is capable of detecting the following system conditions:
[ul][*]hydraulic valve failure[*]wheel speed sensor failure[*]ABS power relay short circuit[*]interconnect failures to the ABS sensors, power and ground to the ABS module[*]over/under voltage conditions [/ul]The ABS provides self-diagnostics and displays failure messages via the ABS indicator in the instrument cluster. Failure of the ABS module, for whatever reason, will not compromise the normal operation of the brake system.
The Dynamic Stability Control (DSC) system includes the:
[ul][*]anti-lock brake system.[*]yaw/lateral control.[*]full speed traction control. [/ul]The DSC system manages the braking system to enhance the driver control of the vehicle.
The DSC system continually monitors the steering wheel angle, master cylinder brake pressure, front and rear wheel speeds, vehicle yaw and lateral rate acceleration.
The yaw/lateral rate sensor supplies a signal to the DSC module, via a serial link, which monitors the vehicles rate of acceleration from its central axis in a sideways direction, and also the vehicles angular rotation around it's central axis.
The driver input parameters are continually monitored via the brake master cylinder dynamic stability control sensor, the brake pedal travel sensor and the steering wheel angle sensor.
DSC is enabled/disabled via the traction control ON/OFF switch.
Self-diagnosis of the DSC system is provided via the instrument cluster message centre.
Traction control is an additional function added to the ABS/DSC system. The vehicles driven wheels are continually monitored for wheel spin relative to the calculated reference speed and to each other. If wheel spin is detected, the traction control function intervenes independently of the driver, applying brake pressure to the slipping wheel and reducing the engine drive torque supply. Meanwhile, brake pressure is modulated by the traction control until traction is re-established. Traction control brake actuation is diminished above 40 km/h (25 mph). Above this speed traction control relies primarily on engine torque reduction.
Traction control is enabled/disabled via the traction control ON/OFF switch. When the switch is in the (OFF) position, the amber traction control warning lamp solidly illuminates within the instrument cluster message centre. The traction control is automatically activated when the ignition is switched on. Self-diagnosis of the traction control system is also provided via the instrument cluster message centre.
The traction control brake intervention is automatically disabled whenever the brakes exceed a temperature limit. The traction brake intervention will remain disabled until the brakes have cooled, irrespective of ignition switch position or ignition switch cycling.
[sm=wtf.gif]
#42
08-14-2013, 07:55 PM
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DSC/ABS/Check Engine Light
Nice post on how the system works. Having the same issue and just posted a quick reply to your original. Looking for help on troubleshooting my issue. replaced ABS control unit and it cleared all faults until I started driving and the DSC came back and shortly after the ABS light along with Check Engine Light came on.
#43
05-30-2015, 11:01 AM
Hi.
1997 Xk8 4L.
After disconnect the battery I take off the central panel for check the core heater. Find the leakage of the antifreeze. Fix it. And assembled all back.
Engine starting normal. No failure messages. All clear.
But the Traction control don't turned off. When I press the Traction Control button, the lamp on this button turn on, and after 3-10 seconds turn off. When I push the Traction Control button next time (any times) the lamp on this button not light.
No any failure messages.
Help me please, tell me what must I do?
1997 Xk8 4L.
After disconnect the battery I take off the central panel for check the core heater. Find the leakage of the antifreeze. Fix it. And assembled all back.
Engine starting normal. No failure messages. All clear.
But the Traction control don't turned off. When I press the Traction Control button, the lamp on this button turn on, and after 3-10 seconds turn off. When I push the Traction Control button next time (any times) the lamp on this button not light.
No any failure messages.
Help me please, tell me what must I do?
#44
08-23-2015, 02:34 PM
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#45
08-24-2015, 01:24 AM
Veteran Member
#46
11-04-2015, 11:06 PM
Hi FactoryJaguarTech,
I have Jaguar XFR 2010, and driving with "ADAPTIVE DYNAMICS FAULT" all time, i check all fuses, pulled out all modules from under the passenger seat they looks fine now I'm thinking to check the yaw rate sensor, couldn't find could not find yaw rate sensor.
Do you know where is that located?
Appreciate your effort and spending time to explore really mind blowing stuff.
I have Jaguar XFR 2010, and driving with "ADAPTIVE DYNAMICS FAULT" all time, i check all fuses, pulled out all modules from under the passenger seat they looks fine now I'm thinking to check the yaw rate sensor, couldn't find could not find yaw rate sensor.
Do you know where is that located?
Appreciate your effort and spending time to explore really mind blowing stuff.
#47
11-05-2015, 02:29 AM
I have Jaguar XFR 2010, and driving with "ADAPTIVE DYNAMICS FAULT" all time, i check all fuses, pulled out all modules from under the passenger seat they looks fine now I'm thinking to check the yaw rate sensor, couldn't find could not find yaw rate sensor.
Do you know where is that located?
Do you know where is that located?
(click on the image to enlarge it - see item 5)
It's hidden under the parcel shelf:
(click on the image to enlarge it)
A yaw sensor is fitted to several Jaguar models and I can't recall reading reports of failures on the forums.
Graham
#48
05-28-2016, 07:54 PM
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I have a 2003 xk8 with a constant DSC FAULT ERROR on my dash I have put a couple of thousand miles on it and for very few miles, the light has gone off and coincidently the red lite on the ABS switch will come on. Next time i start the viehicle the DSC warning will come back on. I have taken it to several car repair places and 2 have said that I need a steering wheel position sensor. I have also been told that this is the same as the steering wheel angle sensor. I am beeing told that the sensor is only available with the purchase of the entire upper end of the steering shaft for about 2,400 for the part. I am begining to think something is fishy here and wanted to know what you think about this and should I in actuality be checking my brake fluid level? I'm confused as hell. Also can you direct me to a pdf of all the parts in a blowup of it in proximity to the steering mechanism?
#49
05-29-2016, 03:40 AM
This is a regular issue on the XK8/XKR and you will find plenty of threads and information in that forum.
I've deleted your identical question from X350 forum.
Please follow this link New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum to the New Member Area - Intro a MUST forum and post some info about yourself and your vehicle for all members to see. In return you'll get a proper welcome and some useful advice about posting to the forum.
Graham
#50
05-30-2016, 08:00 AM
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#51
05-30-2016, 09:03 AM
X350 is the factory designation for XJ four door saloons produced from 2003 to 2009.
Graham
#52
01-03-2020, 11:08 AM
Traction control issue
Hi there I noticed your info on traction control and abs modules and wondered if you could help me, I have a 2000 manual s type 3.0 I recently changed the rear track rods as not fail and since then on accelerating from standstill the n/s rear wheel always seems to loose traction and the traction control light flashes on dash, this also happens on a straight road at speed I can only describe the sensation is as if that side gives way or slips out making the back end fish tail a little, could I have disturbed the wire when changing the track rod on that side I don’t even recall seeing the wire when changing, bizarrely the same thing happened a few months ago on my auto version same year same mot fail same replacement then the same issue happens?
any advise would be grateful kind regards
any advise would be grateful kind regards
#53
01-03-2020, 11:16 AM
Veteran Member
#54
01-03-2020, 12:11 PM
hi the rear tyres were both worn evenly so I assumed the old track rods were adjusted correctly and therefore altered the new rods to the same length as the old ones via a block of wood with two holes drilled in and he old trackrod and new one placed in each hole next to each other with a block and spirit level on top, I counted the thread left after adjusting to make sure all ok and corresponding with old track rods, this is how I’ve always adjusted track rods on any car and it’s never been an issue unless the jag is more sensitive and needs a garage laser alignment?
#55
01-04-2020, 06:33 AM
Veteran Member
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