Traction light flashing 45-80 mph

[Squirrel]

I notice when I'm accelerating on the on ramp or drive on the highway usually slightly turning my traction light flashes and activates. It never comes on below 45 mph. i pulled codes and i always get rear wheel speed codes, I pulled both rear wheels and rotors. Both rear sensors are tight and have no damage. E-brake shoes and sensor rings are ok. I monitored wheel speed and I can see both the rear sensor spike or drop out quickly and when they spike back to back thats when the light comes. Before i try new sensors i wanted to see if anyone else has seen this before.

[fastblackmerc]

I notice when I'm accelerating on the on ramp or drive on the highway usually slightly turning my traction light flashes and activates. It never comes on below 45 mph. i pulled codes and i always get rear wheel speed codes, I pulled both rear wheels and rotors. Both rear sensors are tight and have no damage. E-brake shoes and sensor rings are ok. I monitored wheel speed and I can see both the rear sensor spike or drop out quickly and when they spike back to back thats when the light comes. Before i try new sensors i wanted to see if anyone else has seen this before.

Check the bolts that secure the sensors, they have been known to come loose.

[Squirrel]

bolts are tight. thanks

[FordNut]

What size tires are on it?

[Bluerauder]

What size tires are you running front and rear ?? You might be right on the edge of the acceptable range difference when factoring in tire wear.

[Squirrel]

i was thinking that also
front 235-55-18

rear 255-55-18

[RubberCtyRauder]

3.1% difference, should be ok

[ctrlraven]

3.1% difference, should be ok

I got 2.8%.
235/55R18 is 28.2"
255/55R18 is 29.0"


How long has this been going on for?

Did you change tire sizes and notice this start to happen?

[Squirrel]

I just bought the vehicle last month so i'm not sure and the way the speed signal drops out it seems more like an circuit or sensor concern. I'm getting new tire soon so i might hold off and see if the new tires fix it

[fastblackmerc]

How about removing and cleaning the sensors at each wheel?

Broken teeth on the tone ring(s)?

[RubberCtyRauder]

I got 2.8%.
235/55R18 is 28.2"
255/55R18 is 29.0"


How long has this been going on for?

Did you change tire sizes and notice this start to happen?

I got 28.18 and 29.04,so we are .060 apart

[ctrlraven]

When I had to run the stock (235/50R18) front size on the rear for a short period of time my traction control light would come on around 45 mph if I didn't turn the traction control off after starting the car.

I'd bet it's due to the tire size being too close. Need to have a minimal of 1.2" difference in tire diameter from the front to the rear.

[Lowndex]

I got 2.8%.
235/55R18 is 28.2"
255/55R18 is 29.0"


How long has this been going on for?

Did you change tire sizes and notice this start to happen?

Try Common Core Math :)

[Lowndex]

When I had to run the stock (235/50R18) front size on the rear for a short period of time my traction control light would come on around 45 mph if I didn't turn the traction control off after starting the car.

I'd bet it's due to the tire size being too close. Need to have a minimal of 1.2" difference in tire diameter from the front to the rear.

For 11 years, I have used 235/45/18 and 255/55/18 tires with no issues = ctrlraven raises a good point.

[RubberCtyRauder]

I got 2.8%.
235/55R18 is 28.2"
255/55R18 is 29.0"


How long has this been going on for?

Did you change tire sizes and notice this start to happen?


I think Paul (blackend300a) runs these sizes as he was running the nitto 420 and I know he had the 235-55-18 fronts

[Bluerauder]

Difference is right at 3.05%. 1/8 inch (3 millimeter) wear on the rears would put the delta at 2.60% or very close to the lower end of the acceptable range.

[lifespeed]

Any chance your bearings and axles are shot? I've never let them get so bad they hit the wheel speed sensor, but it is theoretically a possibility.

Tire sizes do seem the obvious place to check.

[EMAS]

Is it just one sensor that shows the drop out or is it multiple sensors and which one(s) are they?

If more than one drops out do they drop out at the same time?

I've seen a slightly damaged tooth on the tone ring cause similar problems. In that case it was on a Windstar that the trans shop had dented a tooth in the process of pulling that axle. Once the speed got high enough the sensor seemed to miss that tooth that was smushed down just a little bit. It took a very careful tooth by tooth inspection to see it. Replacing the tone ring fixed the drop out.

[lifespeed]

Is it just one sensor that shows the drop out or is it multiple sensors and which one(s) are they?

If more than one drops out do they drop out at the same time?

I've seen a slightly damaged tooth on the tone ring cause similar problems. In that case it was on a Windstar that the trans shop had dented a tooth in the process of pulling that axle. Once the speed got high enough the sensor seemed to miss that tooth that was smushed down just a little bit. It took a very careful tooth by tooth inspection to see it. Replacing the tone ring fixed the drop out.

Now you've got me nervous about my custom tone rings for a floating-hub 9" Ford rear! Hope they work. Maybe annealing for maximum magnetic permeability will be required after all . . . :(

[Bluerauder]

IMHO the tire size would be the first and obvious place to check. After 12 years on the MM.Net Forum most of the issues with Traction Control flashing have been related to mismatched tire sizes. The sensors come in at a very distant second at near 100 to 1. Rear tire height Should be 3-6% greater than the fronts. Anything larger or smaller can trigger the speed sensor into thinking that it is detecting wheel slip and cause the TC light to flashing. Your sizes are marginal and right at the lower end of the acceptable range when the tires are brand new. Since rear tires on the Marauder wear faster than the fronts, the difference would continue to decrease until they drop out of the lower end of the range. 235/50/18s on the front would be a better choice IMHO and give you a better range tolerance to work with. Because you have not mentioned a power drop out when the TC light flashes, I suspect that the TC is trying to tell you that the limit has been reached on the tire size difference. It will only get worse as the rears wear.

[Bluerauder]

I think Paul (blackend300a) runs these sizes as he was running the nitto 420 and I know he had the 235-55-18 fronts


Paul's car is a 2003 -- 300A, so Traction Control and tire size is not an issue for him.

[nh muscle]

I run either 295 45 18 or 305 45 18 in the back and stock size in the front never had a problem in 10 years

[lifespeed]

Paul's car is a 2003 -- 300A, so Traction Control and tire size is not an issue for him.

He doesn't have ABS? It seems nobody here has figured out the ABS system is watching those tone rings and wheel rotations also.

Try swapping wrong size tires on the car and doing some threshold braking. Notice the ABS triggering too early? :rolleyes:

[EMAS]

He doesn't have ABS? It seems nobody here has figured out the ABS system is watching those tone rings and wheel rotations also.

Try swapping wrong size tires on the car and doing some threshold braking. Notice the ABS triggering too early? :rolleyes:

The ABS function looks at each sensor's output individual looking for a rate of deceleration that indicates wheel lock up and doesn't compare the values between the different sensors. So no the ABS does not trigger too early on a 300a that does not have the stock or at least close to the stock stagger.

[Bluerauder]

The OP has enough information in this thread to address the TC problem. I look forward to hearing his final resolution to the issue. My bet is on tire size.

[lifespeed]

The ABS function looks at each sensor's output individual looking for a rate of deceleration that indicates wheel lock up and doesn't compare the values between the different sensors. So no the ABS does not trigger too early on a 300a that does not have the stock or at least close to the stock stagger.

My experience, as well as other Marauder owners I have spoken with, has been the ABS kicks in too early with 255/55 rear and stock front. I thought the ABS was the same both years?

It was a noticeable problem that disappeared with the correct stagger.

[Bluerauder]

My experience, as well as other Marauder owners I have spoken with, has been the ABS kicks in too early with 255/55 rear and stock front. I thought the ABS was the same both years?

It was a noticeable problem that disappeared with the correct stagger.


Don't know who you have been talking to; but I ran the 255/55/18 GoodYear Eagle F1 DS-G3 with the stock BFG g-Force KDWS 235/50/18 fronts for 2 years without any TC or ABS problems at all. I know several other owners who used that same combo without issue.

[martyo]

Try Common Core Math :)

Common core will cost you money!! ;)

[Logizyme]

DTC's?.....

[FordNut]

My experience, as well as other Marauder owners I have spoken with, has been the ABS kicks in too early with 255/55 rear and stock front. I thought the ABS was the same both years?

It was a noticeable problem that disappeared with the correct stagger.


Don't know who you have been talking to; but I ran the 255/55/18 GoodYear Eagle F1 DS-G3 with the stock BFG g-Force KDWS 235/50/18 fronts for 2 years without any TC or ABS problems at all. I know several other owners who used that same combo without issue.

I had problems.

[Turbov6Bryan]

My experience, as well as other Marauder owners I have spoken with, has been the ABS kicks in too early with 255/55 rear and stock front. I thought the ABS was the same both years?

It was a noticeable problem that disappeared with the correct stagger.

I am currently running new Firestone 235/50/18 and sumitomo 255/55/18 on a 2003 300a and I've never had early abs kick in

FYI the rears were used, so possible since they were worn 1/4 of the way I have gotten lucky!

[RoyLPita]

Change out the front tires to 235/50r18 stock. That should solve this issue.