Over 75+ Mph ABS Light Comes On

[SenorNoob]

Could a difference in tire pressure cause problems with ABS?

 

[don4331]

It could, but the tire would need to be nearly flat.

The difference in loaded radius between e.g 25 and 40 psi is very small.​

The difference in loaded radius between e.g. 10 and 25 psi is more.​

​

But I would think one would notice the low pressure at 75+ before the the ABS light.

You're more likely to notice the light coming on as a "traction control" - the 40 psi tire spinning/locking up before the 25psi one. But that would be low speed, not at freeway speeds.

 

[DeadEye200321]

The sensors are measuring the difference between the wheels to determine if you one (or more wheels) have an issue (focus is on braking, but it's checking all the time). So, if for whatever reason (wear, tire pressure, size) there is sufficient difference, the module flags it. Therefore, if one tire has worn more than other (poor alignment, etc); then when you fast enough you can trigger the flag.

That said, if you have had issues with the spider gears, I would start with the rear sensor (the one on my daughter's '02 Explorer "wore out" <lost ability to sense> ) and was causing ABS issues. Our vehicles are getting over 20 years old and that's longer than Ford planned for some of the parts to last.

Cleaning all the debris out of the axle tubes is PIA. Remember, oil goes all the way to the wheel bearings...

So I did check the rear abs sensor and there was metallic fuzz around it, so I cleaned that off and the issue is still persisting. I did notice the bottom of the sensor looked a tad bit chewed up with a few scuff but nothing too terrible, could that mean the sensor got damaged when my spider gears got destroyed because I would imagine the bottom of the sensor is protected with a plastic covering but I could be wrong, would replacing that sensor be my best and least costly trouble shooting method next?

 

[DeeRanger]

Mine comes on also at speeds over 70mph. I thought it was a safety feature and that the ABS stands for Always Be Safe...?

 

[ekrampitzjr]

The warning light is your guardian angel trying to send you a message about driving your Ranger above 75 mph.

 

[DeadEye200321]

I did not have this problem before, so I know my Ranger can handle a constant speed of 85 to 90 mph, so I don’t think that it’s that my truck can’t handle that speed.

 

[DeadEye200321]

I will say that when I was driving the other day, I wasn’t exactly at 75mph, maybe 72 or 73mph and on this part of the freeway there’s a kind of larger pot hole type groove ish thing in the freeway that isn’t a particular issue that I’m worried about damaging my truck but it’s like some layer of the freeway is missing and the layer below is exposed which makes the freeway a little uneven, and I went through/over it and it is maybe like 2 ish meters long, and within 15 seconds my abs and brake light came on. You definitely feel when you go through the groove in the freeway but it’s not like hitting a pothole where your cab jerks. So from this I would imagine sudden rough-ish changes in movement at high speeds most likely above 70 cause the sensor to come on, so maybe a vibration? Maybe a worn rear axle bearing, although I did replace my outer axle bearings and properly lubricated them with differential oil before installing the axles again so I doubt that it is worn. Maybe front hubs are getting worn and causing the abs sensors to have incorrect readings and need replaced? Only question with this hypothesis is that the abs codes mentioned in the beginning of this post suggest from abs sensors just have a mis reading whereas the rear abs sensor appears to not have a signal or signal error code. Maybe the rear abs sensor is worn or damaged and needs replaced? Lastly maybe the abs module itself is malfunctioning and needs replaced, but that does look like a lot more work since it looks like hard tube brake lines go to it. Please if anyone has more insight into this issue please let me know or give me some suggestions, I’m going to replace the rear abs sensor now as it’s relatively cheap and easy to do. Thank you everyone!

 

[lil_Blue_Ford]

Do you have access to a scan tool that can read data or Forscan and a cable? Not all scan tools can but I actually have used Forscan on my laptop to diagnose an ABS problem in my green Ranger. I got a generic sort of error code, but there’s a way in Forscan to watch the data live and I watched the sensor readout as I drove around until I saw what sensor was flaking out on me and reading off from the others.

I did end up after that with an ABS problem that I needed a shop manual to diagnose and gave up on the system and pulled the fuse for the pump. Then I replaced the entire ABS when I swapped motors. It’s not all that hard to swap other than you have to bleed the entire brake system. Part of me wonders if I should have just eliminated the ABS, I’m not a huge fan of the system especially when it acts up in older vehicles.

 

[superj]

i am not either. i know what its for but i know that is also why we now have to have back up monitors and lane departure warnings and crap like that

 

[ekrampitzjr]

I did not have this problem before, so I know my Ranger can handle a constant speed of 85 to 90 mph, so I don’t think that it’s that my truck can’t handle that speed.

You know I was clowning.

 

[ekrampitzjr]

Do you have access to a scan tool that can read data or Forscan and a cable? Not all scan tools can but I actually have used Forscan on my laptop to diagnose an ABS problem in my green Ranger. I got a generic sort of error code, but there’s a way in Forscan to watch the data live and I watched the sensor readout as I drove around until I saw what sensor was flaking out on me and reading off from the others.

I did end up after that with an ABS problem that I needed a shop manual to diagnose and gave up on the system and pulled the fuse for the pump. Then I replaced the entire ABS when I swapped motors. It’s not all that hard to swap other than you have to bleed the entire brake system. Part of me wonders if I should have just eliminated the ABS, I’m not a huge fan of the system especially when it acts up in older vehicles.

I've been pondering what to do if the ABS starts giving me problems. In my entire driving life (45 years) I have locked brakes maybe half a dozen times. If an expensive repair becomes necessary to the system, pulling the fuse and removing the warning light in the dash looks like an attractive option.

If you're making panic stops locking the wheels all the time, you need more than ABS.

 

[lil_Blue_Ford]

At least you can still stop with the Ranger system even if it screws up…

GM… not so much… you lose everything when the system takes a dump. And the dealers fix is to pull lights and fuses and cut wires…

 

[SenorNoob]

Brittney had a GM truck for a couple months that had a habit of after you'd been somewhere awhile it would either lock up all 4 brakes. Or unlock all 4 brakes. Never knew if was gonna not move or not stop.

 

[DeadEye200321]

Been MIA but it ended up just being the stupid rear abs sensor LOL. Thanks for all the help everyone!

 

[Curious Hound]

Thanks for the follow-up. Glad you got it fixed.