ABS/PSM failure - tire size??
06-18-2018, 04:06 AM
#1
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ABS/PSM failure - tire size??
I’ve intermittently been having the ABS and PSM lights come on while driving. It doesn’t seem to happen during any particular type of driving, just randomly. There is no noticeable issues with drivability when the lights come on. I’ve also scanned for codes and nothing comes up. The lights go off when the car is shut off for a few minutes.
I recently read about tire sizes and how it impacts the all wheel drive system. The PO put 305/30 19s in the rear and 235/35 19s in the front. When I use a tire diameter calculator that shows only a 3.5% difference. Could this be causing my issues?
Thanks!
I recently read about tire sizes and how it impacts the all wheel drive system. The PO put 305/30 19s in the rear and 235/35 19s in the front. When I use a tire diameter calculator that shows only a 3.5% difference. Could this be causing my issues?
Thanks!
06-18-2018, 10:26 AM
#2
RL Community Team
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This is just my opion but would consider the difference of diameters of those tires to not be compatable with the AWD/PSM system. Not even close to being correct.
06-18-2018, 12:57 PM
#4
Three Wheelin'
Your tire sizer are way off . 305-30 19 is 26.2", 235-35 19 is 25.5 and the stagger is in the wrong direction. You need the smaller diameter in the rear (turns faster) to drive some torque to the front wheels. I had the stagger off by about 25% as much as you (smaller in the front) and was having random ABS events. Switched to stock sizes and it has never happened again in 20K miles. All kinds of post on here about how this or that worked fine for me. But if you want the AWD system to work properly, stick with standard tire diameters and stagger. Those boys didn't just finish their schnitzel and just pick a tire size, it is designed to function as a system and all the parts need to be properly sized.
06-18-2018, 06:57 PM
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Ok sounds like PSM/ABS issues may be unrelated (I’ll check battery voltage. That could be it.), but either way the tire size is way off. Honestly, in two years of owning the car I never really noticed I was running 305s in the rear.
The tires are still in decent condition - I probably have a year or two left on them with how often I drive the car. Any thoughts on how immediate of an issue this is to solve? Does this damage anything? Does it create any safety issues with the handling? Or is this really “you’d have better track handling with the proper tire sizes” - in which case I’d solve it when I need some new tires in the coming year or two.
(I don’t track the car at this time - if I start to, I’ll be making a bunch of changes including tires)
Thanks everyone!!
The tires are still in decent condition - I probably have a year or two left on them with how often I drive the car. Any thoughts on how immediate of an issue this is to solve? Does this damage anything? Does it create any safety issues with the handling? Or is this really “you’d have better track handling with the proper tire sizes” - in which case I’d solve it when I need some new tires in the coming year or two.
(I don’t track the car at this time - if I start to, I’ll be making a bunch of changes including tires)
Thanks everyone!!
06-18-2018, 07:23 PM
#6
Three Wheelin'
Disclaimer: The following numbers are based on Tire Rack's specs for Michelin PS4S.
The only front tire i see working (mathematically) with your current rear 305s is a 235/40ZR19 which is 26.4" tall yielding 787 revs per mile. This matches well to the 305/30 which are 26.3" tall yielding 792 revs per mile.
The real question is will a 26.4" tire work on the front of your car? Stock ride height maybe ok. Lowered, I'm not sure, but others will know.
Another potential combo would be 225/40/19 matched to 295/30/19s, both around 26.0" tall with the fronts turning 797 revs per miles vs the rears turning 799.
There have been many threads regarding tire heights and front to rear sizing that derives from how our AWD system works.
The only front tire i see working (mathematically) with your current rear 305s is a 235/40ZR19 which is 26.4" tall yielding 787 revs per mile. This matches well to the 305/30 which are 26.3" tall yielding 792 revs per mile.
The real question is will a 26.4" tire work on the front of your car? Stock ride height maybe ok. Lowered, I'm not sure, but others will know.
Another potential combo would be 225/40/19 matched to 295/30/19s, both around 26.0" tall with the fronts turning 797 revs per miles vs the rears turning 799.
There have been many threads regarding tire heights and front to rear sizing that derives from how our AWD system works.
06-18-2018, 10:02 PM
#7
Rennlist Member
Tire size mismatch will not set off a PSM ABS failure light,while randomly driving. A tire mismatch will usually activate the PSM while driving, particularly around corners!
Could be a voltage issue, or your brake lights are not working, bad brake light switch. I also heard it could be be your MAF is on its way out, or dirty, speed sensor, abs ring.
Could be a voltage issue, or your brake lights are not working, bad brake light switch. I also heard it could be be your MAF is on its way out, or dirty, speed sensor, abs ring.
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06-19-2018, 10:44 AM
#8
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I've counted about 10 different things that can set this off.
- Speed Sensor
- Maf Issue
- Voltage Issue
- Brake Light Switch
- etc
For me, i had a seized wastegate that was causing this.
- Speed Sensor
- Maf Issue
- Voltage Issue
- Brake Light Switch
- etc
For me, i had a seized wastegate that was causing this.
06-19-2018, 11:42 AM
#9
I had the exact same issue. For me, when I would be driving at normal highway speeds, and accelerate to pass my PSM ABS failure light would come on as well. After shutting off the car and restarting it, the failure light would be gone. I took the car to my local indy shop, they are one of the oldest in the country and I really trust these guys, and explained the problem I've had. They said it was due to my non OE winter tire sizes. I run 265 in the rear because I couldn't find 295's in a snow tire. Once I switch to my summer set of wheels and tires, both OE, I never get that issue. While there are a bunch of different things that could set it off, for me it was 100% the non OE tire sizes.
06-20-2018, 10:46 PM
#11
In my case it was the brake light switch.
Can you share PN & instructions? I'm fighting this right now. Speed sensor fault - replaced. It cut down but did not eliminate the PSM/ABS fault. I just replaced my original 2002 MAF but still have about the same error rate.
My next step is to fix the ABS module if the brake light switch doesn't work. I just have a hard time that the brake wiring harness may be bad as my car has never been lowered.
Can you share PN & instructions? I'm fighting this right now. Speed sensor fault - replaced. It cut down but did not eliminate the PSM/ABS fault. I just replaced my original 2002 MAF but still have about the same error rate.
My next step is to fix the ABS module if the brake light switch doesn't work. I just have a hard time that the brake wiring harness may be bad as my car has never been lowered.
06-21-2018, 03:56 PM
#12
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I'm going with incorrect tire sizing . See road kings recommendation.
Alternately, you're not harming anything with intermittent abs/psm. Just a nuisance at the pace you seem to be driving.
Alternately, you're not harming anything with intermittent abs/psm. Just a nuisance at the pace you seem to be driving.
06-21-2018, 04:48 PM
#13
I get the error to sometimes. I changed the brake light switch, new battery, and cleaned the speed sensors. Note, this is with stock tires with correct tire pressure. I upgraded my wheels and tires to GT2 size. Still have the error with consistence time or errors. I'm not convince its the MAF. It's something else small and simple.
06-21-2018, 06:06 PM
#14
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Ok - so I’m not doing any long term damage with the tire sizing?
Going to try the brake light switch to see if that fixes the PSM/abs lights. Thanks.
Going to try the brake light switch to see if that fixes the PSM/abs lights. Thanks.
06-21-2018, 07:50 PM
#15
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