ABS sensor seems to be linked to everything!

[dazzabb]

I had the ABS, DSC and FTM warning lights all come on 2 days ago.

I was fearing the worst after reading some posts about $2,500 + pump replacements etc.

Turned out it was just a bad ABS sensor on the left front, changed that and all warning lights were gone.

I've tried searching for the "relationship" between these various lights and ABS but can't find the answer.

Could somebody briefly explain why and how DSC and FTM could be affected by ABS?

Thanks Daz

[d0o0fy]

ABS, DSC and FTM all use the same wheel speed sensors. That's why when yours went bad all three systems showed errors.

FTM monitors the difference in velocity between the four wheels that would indicate a change of tire pressure. Lower pressure, means decreased circumference and therefore lower rotational speed. If it differs from the other wheels by a significant amount the FTM system will warn of low tire pressure.

DSC combines differential wheel velocity with other sensor readings (gyroscopes, steering) to detect over/under-steer conditions and generate corrective actions.

[dazzabb]

Good info, thanks.

[Longboarder]

Originally Posted by d0o0fy

ABS, DSC and FTM all use the same wheel speed sensors. That's why when yours went bad all three systems showed errors.

FTM monitors the difference in velocity between the four wheels that would indicate a change of tire pressure. Lower pressure, means decreased circumference and therefore lower rotational speed. If it differs from the other wheels by a significant amount the FTM system will warn of low tire pressure.

DSC combines differential wheel velocity with other sensor readings (gyroscopes, steering) to detect over/under-steer conditions and generate corrective actions.

Not a bad 3rd post. Thx.

I experienced this exact thing this summer at the track but it wasn't because of a bad sensor, it was because I was spinning my rear tires so much that ABS failed! Cliff notes: 97 degrees afternoon track session at Big Willow and I'm running street tires (Michelin PSS). Tires can't handle the heat and actually begin to break down into a gooey substance. It's so bad, that I have no traction accelerating at anything more than half throttle. Because of the sustained tire spin, ABS turns off - but so does everything else! My NAV lights up like a Christmas tree and everything turns off, including DSC.

I track with Euro MDM on, so DSC is on as well. In this instance where ABS failed, I could deal with that but didn't know DSC had also failed so I wasn't being very cautious on my warm down lap and this happened:

http://www.m3post.com/forums/showpos...&postcount=615

[CanAutM3]

Originally Posted by d0o0fy

ABS, DSC and FTM all use the same wheel speed sensors. That's why when yours went bad all three systems showed errors.

FTM monitors the difference in velocity between the four wheels that would indicate a change of tire pressure. Lower pressure, means decreased circumference and therefore lower rotational speed. If it differs from the other wheels by a significant amount the FTM system will warn of low tire pressure.

DSC combines differential wheel velocity with other sensor readings (gyroscopes, steering) to detect over/under-steer conditions and generate corrective actions.

All good, except for one small detail. It is not really the tire's physical circumference that changes, but rather the effective rolling radius that is decreased and this leads to a HIGHER rotational speed .

[d0o0fy]

Originally Posted by CanAutM3

All good, except for one small detail. It is not really the tire's physical circumference that changes, but rather the effective rolling radius that is decreased and this leads to a HIGHER rotational speed .

Correct, my mistake. Let's say I should try to math on a Saturday night that late