ldc6

I'm experiencing a problem that I know a few others have had (I've done a search and the info I've found has helped but not fully).

After going around a hard right turn (haven't tried left), a specific set of dash lights come on (ABS, emergency brake, traction control) ... see pic:


More specifically, I go around the turn pretty hard, straighten out, and then when I go to press the brakes, I get the ABS (eventhough I'm only tapping the brakes) and then all those damn lights come on. I'm concerned because I tested to see if my ABS was actually still working when all those lights are on and it is NOT. The lights go off, however, when I restart the ignition and everything's fine.

Things of note:
-I have not been able to reproduce this with my stock wheels and tires on.

- Occurs with my aftermarket wheels on (no TPMS). I have a staggered setup (8.5s and 10s; rolling diameter delta is ~.1"). No other mods.

- I have checked the connections on the ABS sensors as others have had success with that, but all connections are tight. And if it were a bad sensor I would think that it wouldn't matter which wheels I had on. Also checked to make sure the wheels aren't butting up against the wires.

-I had brought it in to the dealer, but had put my stock wheels back on (didn't know at the time that I couldn't reproduce the problem with them on). Since they couldn't reproduce the problem, they said everything was fine. I asked them to check the ABS sensors, but they didn't. They also said no code was stored.

- I don't want to bring back to the dealer with my aftermarket wheels on b/c I don't want them giving me cr@p about them. I can't imagine it's the wheels themselves causing problems (perhaps I'm wrong), but I feel that's what they'll blame it on if I bring it in with them on.

Any ideas? At first I wasn't too concerned because I know I could reset it, but after realizing that my ABS and probably TSC are disabled because of it I'm a little more worried about it.

Thanks,
ldc

KYLiquid

brake fluid level looks ok right?

Dark8

Posted by ldc6:
- I have not been able to reproduce this with my stock wheels and tires on.
- I can't imagine it's the wheels themselves causing problems....

Sounds like the wheels are the problem if it happens only when they are on the car. Don't believe posted specs on tires. Measure them for yourself and see what the difference is.

ldc6

yeah, brake fluid level is fine... almost max. thanks.

Yeah, I knew someone would call me out on that. What I meant is that I can't think of a logical reason why it would be the wheels themselves. If that were the case I would think many more people would be having this problem.

I thought initially that it might have something to do with not having the TPMS sensors, but I can't see how that would be linked to those particular lights and again more people would be experiencing the same issue. Perhaps it's somehow related to having more grip, but again I'm not sure what that would affecting. Perhaps more lateral force is moving something around that shouldn't but I have no idea what.

I'll try and measure the difference more accurately like you suggested. But even if there is a slightly bigger delta, how would that cause this problem? I don't know much about this kind of stuff, but I would think that would affect the DSC, which doesn't appear to be turning off (or at least that light is not coming on) .

KeithL

I agree. I could see how the difference in the tire diameters might cause both the ABS and DSC to think your wheels are spinning. Don't know about the brake light though... That might be related to the ABS warning light. The tire circumference is 3.14 x (dia.), so, the larger ones would be rolling some small fraction of a revolution less than the smaller ones...

Razz1

Disconnect the battery and hold the brake pedal for 30 secs.

That will reset the ECU.

ldc6

Ok, so I tried resetting the ECU and low and behold I have a new set of lights instead. After I reset I turned on the ingition and the "DSC off" starts flashing and the squiggly car light is on. That is without driving the car anywhere, just simply restarting in the driveway.

p.s. I tried the NVRAM and KAm resets and got the same result.

wtf?!?!

ldc6

update #2: I decided to drive around with the flashing "DSC off" light and the squiggly car to see if perhaps they go away after the car runs a bit and sure enough the "DSC off" light went off about a minute into driving. The squiggly car light did not go off until I restarted the car again. So now all lights are off AND I tried a quick test around an exit ramp to see if I could reproduce my original problem (abs, e-brake, and squiggly car lights) and it appears as if things are now good. When I tapped the brakes after coming out of the turn,the ABS kicked in a little but the light did NOT come on!!!

So thank you all for your input, especially resetting the ECU. I'm guessing the ECU reset recalibrates the sensors to whatever it is currently sensing and all is good. I'm curious as to whether I will have the same problem when I put the stock wheels back on, but I'll cross that hurdle when it comes.

Thanks again.

ldc6

ok... so I guess resetting the ECU didn't do the trick afterall. I've had the lights go on a handful of times since. I'm going to try and take it into the dealer... again.

Frostee

there was thread on here (i think) about why not to use staggered wheels. i dunno if that would help at all

gh0st

same thing happened to my mazda 6s only it only happened as i passed 100mph. from there i had to turn off the engine to get the lights to go away. the dealership said they wont fix it because they cant take the car to 100mph lol. i didnt really complain much about it because i abused that car like none other.

denward

ldc6

Frostee - thanks for the suggestion. I read through that thread, but didn't see anything relating to this. It was mostly talking about overall handling differences between staggered and non-staggered setups.

ghOst - lol... I can't even imagine the response if I told my dealer it only happened over 100mph. I guess fortunately for me, I don't have to be going that fast to get it to do it.

Gord96BRG

Your ABS system (and DSC system) is calibrated by the factory for the OEM wheels. It doesn't care if the diameter of the tires are exactly the same as the stock tires, but it DOES care if all 4 wheels have nearly the same diameter.

Think how ABS and DSC works - in part, it uses the wheel sensors and compares the rotational rates of the 4 wheels - if they're all turning at the same rate, then all is good. If one wheel is turning much slower than the others while braking - then it may be on the verge of lockup, triggering the ABS to pulse that wheel. If the rear wheels are turning faster than the fronts, then you have wheelspin and the traction control will kick in, etc.

If you have put on a staggered setup, where the rear wheels are always turning slower than the fronts, then you have altered the system parameters and are probably running closer to the design threshholds for allowable speed differentials between the front and rear wheels. You have probably discovered a circumstance (your hard cornering followed by braking) that is confusing the system by registering readings that are outside the allowed parameters, so the system is programmed to shut down if it encounters strange readings.

The fact that this does not happen with your stock wheels/tires supports this theory... so there will be nothing that the dealer can do. Only the factory engineering team could recalibrate the ABS, DSC, and TC for an unequal-sized wheel setup.

ldc6

I see what you are saying but a few things don't seem to support that.

One, why aren't more people experiencing this issue? I'm not the only staggered setup out there.

And two, the difference in diameter between my fronts and rears is LESS than the difference one can experience with unevenly worn tires front and back. In fact, according to Toyo’s website the tires are the EXACT same diameter (25.6”). Now I know there are manufacturing tolerances, but the physical difference should be negligible (I will measure when I get home). And I'm sure Mazda engineers didn't design the tolerances to be so tight that it wouldn't account for people replacing their tires and possibly having unequal treadwear. Having a set of 50% worn tires in the front and new ones in the rear (a typical rear wheel drive car scenario after wearing out the rear tires) would be a difference of 10/32 (.3125”). And, if they did design it with such tight tolerances, then we go back to my first question and ask why aren't more people experiencing this problem? You can't tell me everyone out there has even treadwear front and back.

From Toyo's website: The last number is the diameter.
Front: 245/40ZR18 97Y RD 246030 8.0-9.0-9.5 26 10 25.6
Rear: 275/35ZR18 99Y RD 246100 9.0-10.0-11.0 27 10 25.6

-ldc

rx8spiritR

i have experienced the same problem too
i think it's because the aftermarket wheel and old brake pad that cause the censor to go on.

ldc6

i'm not sure what the logic is with the aftermarket wheel and brake pad... can you explain how that caused a problem? Do you have a staggered setup as well?

mmats69

I had that same thing happen to me but it ended up being a bad ABS speed sensor.

litig8

Just had the same problem occur yesterday night. All 3 (ABS/Brake/DSC) lights went on about 1 min. into driving (after a normal left turn). I'm running 17" Konig Holes with 255/55/17 Toyo Garit HT's. The lights remained on for the drive home. They were all off when I started the car about 1.5 hrs later. Had the rims/tires all last winter with no such occurence.

Have an appt with the dealer tomorrow - ought to be a fantastic waste of time.

ldc6

Sorry to hear that, but if they figure something out at the dealer could you let us know? I got so sick of it, I just took the damn wheels off and put the stock wheels back on and haven't had a problem since.

If you actually have some luck at the dealer that would give me incentive to put them back on and head to mine.

Good luck!

ranger4277

I started a thread about this problem once last year and I do not have a staggered setup. I did however have aftermarket wheels without pressure sensors. (if that has anything to do with it)
Further reference here: https://www.rx8club.com/series-i-trouble-shooting-95/abs-tcs-e-brake-lights-all-once-any-ideas-58122/
and here: https://www.rx8club.com/series-i-tech-garage-22/all-lights-went-66601/
and here: https://www.rx8club.com/series-i-trouble-shooting-95/abs-tcs-airbag-lights-after-hard-turn-67909/

I think mmats69 pretty much has it nailed. In my case it wasn't a bad sensor but probably a slight loss of communication from a loose connection.

ldc6

Thanks for posting those links, ranger4277. I had come across those in my search early on, but like Cool-Blue-Dad noted, in my case it doesn't seem like a bad or intermittent ABS sensor is my problem otherwise it would happen with my stock wheels/tires on too, right? I did check the connections just in case and they seem fine. I thought maybe the aftermarket wheels were somehow hitting up against the sensor, but they had plenty of clearance.

litig8

Went to the dealer today. Sorry to disappoint but as expected: no error codes, no apparent abs/ebrake/dsc problems. Hasn't happened before/since. Dealer's diagnosis - likely due to different dimensions/weight of aftermarket rim (17" Konig Holes). Sound familiar?

ldc6

hmmm... it seems to me that if it were in fact due to you having 17s then; one, you'd have it happen more often and two, a hell of a lot more people would be experiencing the same problem. dealers suck

I'm glad it hasn't happened since though.

In the next few days I'll be trying out my winter wheel/tire combo (17x7 all aroundl) so I'm curious to see what, if anything, happens.

Tony Yayo

Not sure if this is related, as I don't have any LIGHTS on, BUT it could be the worst-case scenario of the DSC/ABS system going crazy...

I have aftermarket rims with no TPM's on my 8; 18x8 +38 all around. In the front, I have the OE 225/45-18 RE040's (nominal OD 25.9''), in the rear 245/40-18 Falken 512's (nominal OD 25.7''). I have not measured them and had no reason to until now. I don't have access to the car right now, anyway -- read on to see why...


The car came with the OE 18x8 TPM +50 rims and 225/45-18 RE040 tires all around. I removed those and had 245/40-18 Falkens and the aforementioned +38 non-TPM rims installed all around. Due to the rear having gross toe out for some reason and shaving 4 rear tires bald, I had the two good remaining RE040's mounted up front and the two good remaining Falkens rotated to the back. I also did the best I could with the tools I had at the time to set the front and rear toe to zero.

After that day, the car would go schitchzo on hard on- and off-ramps (DSC was on). Big grinding/shudder sound that would throw the car a little sideways. No brakes were applied during these occurences. C'mon an offramp with brakes in an RX8?

The dealer checked the suspension and found nothing major loose, broken, or rubbing. Predictably, the dealer was too lazy to drive 1 mile to the highway to take an offramp and could not reproduce my problem. They thought maybe my steering rack was loose but told me to come back next week, as it was probably fine and didn't need to be replaced. ???

A few days later, I checked the suspension myself and found nothing loose either. I also did a quick parking lot alignment in the rain, wind, and dark and got the cambers and casters fairly mild and even L/R. Did not check the toe, but it is minimal now (no telling inner shoulder tire wear). Was planning on checking the toe, but again read on as to why I do not have access to the car!

The morning after the alignment check I headed to an autocross, where I was going to see if the the same high-G corner grinding/shudder occured with my OE 18x8's with TPMs and same-size tires all around. On the way there, I decided to to see if this problem would occur with DSC off.

Well something happened, as the car quickly shot sideways on a mild merge sweeper (a little wet, of course) and I 180'd into a concrete wall at 60 - 70 mph. No chance to see how it behaved on the same-size tires w/ TPM's and the DSC off at the autocross... because I didn't make it there!

I hope on the car's massive rebuild they actually go through the car and try to trace down the bug. If slightly different f/r tire diameters cause the DSC/ABS/whatever to go crazy and lock up tires or the diff or something... it can be dangerous!

If I need to deflate my front tires to get them to shrink 0.2'' and have this not happen again... I'll do it!