My vote for the worst ABS system goes to?

[DougW]

So is the 1500 mark under brake apply or accel? Can you overlay the graphs so I can see the errors between wheel speed? Do you have brake pressure as well to log? Nothing there that should cause an ABS fail so it must be also G or some other CAN trigger. Does it give you any ABS fault codes?
DougW

[ja1217]

Originally Posted by DougW

So is the 1500 mark under brake apply or accel? Can you overlay the graphs so I can see the errors between wheel speed? Do you have brake pressure as well to log? Nothing there that should cause an ABS fail so it must be also G or some other CAN trigger. Does it give you any ABS fault codes?
DougW

Here's a better look at the data, with throttle and brake pressure included:


As you can see, when the ABS shutdown in turn 2 (around 1500ft) I was not on the brakes at all and was actually on the throttle. I was only pulling around 1.1g through the turn which is nothing crazy. I'm assuming a ABS fault code was thrown as the lights came on, but I did not get a chance to pull the code. Too busy pulling into the pits to turn the car off/on again to reset it and get back out there!

Also, the brake pressure data shows that I've been relying heavily on my ABS when slowing down and just slamming on the pedal. Probably ought to work on that.

Here's the video and you can see the lights come on as soon as I drop 2 wheels off:

[stonenewt]

My impression, but I might be mistaken, is that in ja1217's case the ABS ECU has thrown an outright wobbly at something. It may have been that a large enough jolt caused a short term disconnection of a sensor causing the ABS ECU to go into a fail safe mode.

In Element Tuning's case, I think that he has so much grip there's simply too much disparity between what the car is capable of and what the ABS ECU thinks the car can do so goes into a fail safe mode every time you lean hard on the brakes.

[DougW]

Originally Posted by stonenewt

My impression, but I might be mistaken, is that in ja1217's case the ABS ECU has thrown an outright wobbly at something. It may have been that a large enough jolt caused a short term disconnection of a sensor causing the ABS ECU to go into a fail safe mode.

In Element Tuning's case, I think that he has so much grip there's simply too much disparity between what the car is capable of and what the ABS ECU thinks the car can do so goes into a fail safe mode every time you lean hard on the brakes.

Got to see the code, if you are off the brakes then it has to be an out of range from some sensor or trying to apply stability control and confused as to why it can't. All computer nerds need to make a few laps before writing code to understand the system including the driver.
DougW

[dradernh]

What sounds like it might be nice would be a reset button/switch that could be activated while on the track. My race car has an ABS on/off switch, although I've never had occasion to touch it.

[stonenewt]

Originally Posted by DougW

Got to see the code, if you are off the brakes then it has to be an out of range from some sensor or trying to apply stability control and confused as to why it can't. All computer nerds need to make a few laps before writing code to understand the system including the driver.
DougW

Oh god it's all tied in with that as well! This is why I was saying a lot of it may not apply, the system I dealt with was just ABS & dynamic brake bias. No traction or stability control involved.

[DougW]

Originally Posted by stonenewt

Oh god it's all tied in with that as well! This is why I was saying a lot of it may not apply, the system I dealt with was just ABS & dynamic brake bias. No traction or stability control involved.

Yep, abs has the G sensors and VSC as part of it so it can get overwhelmed by out of the box inputs. Just to make it more fun it is behind the left front head light so the G inputs are not near the roll center. I just think all the Nanny's are PMSing.
DougW

[Nigelr32]

I know this is an old thread, but I believe this is the result of a damaged steering angle sensor?