Its still on! I was running a 275/285 combo on my new 17s. the computer was calibrated for 16s, so i figured that was it. got a new computer programmed for 17s, that didnt work. I put 275s on the rear to make it even all the way around. Still didn't work. The light isnt instant, sometimes it doesnt come on for miles, other times its on in a few minutes. What do you guys think?

 

21 views and no one has any input?

 

What have you tried so far?

I'm sure you've checked the 3rd brake light, it could be having contact issues.

Have you checked your wheel speed sensors?

 

checked to see what code you get? lol. that would help also you have the right aspect ratio on the tires right?

 

third brake light is fine. dont know about the sensors

 

i didnt know there was a code for the inop light. and yes, i have 275/40/17 all the way around, and my pcm is calibrated for them

 

i have the same problem, i get a c0986 code and the asr and hand brake light turns on, then after a short while it turns off...haven't had the chance to check what it is...

 

Just found out on my sons car that the wire going to the sensor on the drivers side sensor had gotten worn through by the spiral wrap on the hard brake line. The spiral wrap had worn through the plastic protective sheath and then through both wires insulation. He was getting the intermittent ABS and Traction Control also. We cut both wires in two and soldered them back together and put some shrink wrap over the repair. Slid the convoluted wrap back over the repair and then added another layer of the convoluted wrap for insurance.

At this point neither light is back on the dash. Seems to have repaired this problem.

 

FYI going from 245/50/16 to 275/40/17 requires no computer modification whatsoever. your speedometer is .1% off with the 17s which means you will be 1 mph off at 1000 mph

as for the ABS INOP i had a problem with mine coming on a few years ago and it turned out to be that i needed new pads or rotors. one of the 2 solved the problem. and for the record all the ABS INOP and LOW TRAC issues i had were when i still had my stock 245/50/16 wheels/tires. as i slowed to a stop my LOW TRAC would come on and then the pedal would get really hard and then jump down to almost the floor and then jump back up. it was kind of scary because i think it lengthened my stopping times. then after it did that 3 times the ABS INOP would come on and stay on until the car was shut down and restarted.

 

Adjusting tire diameter setting for your PCM has no control over your EBCM (your brake module). Different computers, you can't tune your EBCM. Adjusting the PCM parameters (tire diameters) is for speedometer accuracy.

 

can you clarify what i posted? i heard that you don't have to adjust the computer when going from 245/50/16 to 275/40/17. i used a miata calculator i found and it shows they are barely different

http://www.miata.net/garage/tirecalc.html

 

I typically don't use those calculators as I'd be relying on someone else’s flash …etc creation and using a correct formula (calculation). Not that they may be incorrect; I'd have to look at the formula or code, which is more work than just plugging the numbers in.

Based on my calculation, in order, the diameter is theoretically 25.6, the second is 25.7, and the actual tire size depends on manufacture specs, tire wear and inflation. The differences are negligible as I believe someone else commented on.

Regardless, PCM tuning adjustment only affects what you see on your speedometer, not ABS.

You can attempt to fix the ABS problem via troubleshooting. You'll need a more sophisticated scanner. Sometimes it’s a simple repair as stated above, others, it can be quite costly.

Unless ABS is something you need or rely on, you can always remove it. You'll never worry about it again and drop about 16lbs from the front of your car. Normal braking will not change...actually you can increase it effectivness with the adjustable proportioning valve if your bias is off. You'll also clean up quite a bit of space and increase air flow. We have a kit to completely remove ABS and TCS replacing it with preformed lines and an adjustable proportioning valve. This gives you the ability to tune your brake systems bias manually...whereas before you have no control over it. I can also walk you through turning your lamps off too...so you don't have to see them glaring in your face.

Good luck whichever way you choose.

 

Normal braking does change when the ABS light is on because the car slides like crazy when you hit the brakes hard (at least with the 97 and earlier models)...so how does removing it change that?

 

Panic braking is not a normal stopping condition. Neither is locking brakes fully not letting up on the pedal. If your bias is off, and you're consistently locking the rears or fronts first...you NEED to bias your brakes so you are able to use all four wheels to help you stop quicker. As soon as one set of tires lock, you've drastically increased stopping distances and created a more unpredictable stopping situation. Optimally, you want all four wheels to stop the car, not primarily fronts or rears. If ABS is not working, there’s a higher probability one set of wheels is locking before the other.

Situations where you're sliding uncontrollably have many factors to consider.

With the ABS system malfunctioning, if you're brake bias is off (many times aftermarket components completely change needs)...the car will not utilize the braking system to its best ability.

ABS systems are not the end all and provide best performance. 3 channel systems are not near as good as a four channel setup. I don't suggest to everyone to remove ABS, if you like it, leave it alone. Nothing replaces safe defensive driving. If an ABS system is continually somehow saving their butt, one should reconsider their driving habits. If you've never felt your brake pedal pulse, you've NEVER used your ABS solenoids. I’m 41 and have owned quite a few vehicles in my life. I can tell you, I have never used ABS (when I actually needed it). On a few vehicles, it’s activated ever so often but when I don’t need it or wanted it to. The same scenario with TCS, never liked it, never wanted it….just another gizmo to troubleshoot or go off when I don’t want it to. I like to think I control the car, not the car control me. These are my own personal thoughts on the matter though, others may vary which is fine.

What most overlook is the ABS system is configured for your STOCK car. When you change wheels, tires, brakes, rotors change weight distribution etc, the ABS system is not configured to its original design intent. Since you cannot tune your ABS system, a simplistic comparison would be like changing heads and a cam on your car and not considering retuning your PCM computer. …The car wouldn't not run as it was initially intended nor would you be taking full advantage of the heads and cam change.

…The people who use varying tire sizes or other similar significant changes to their car and feel safe continuing to rely on their ABS system to get out of all situations…put another coin in the wishing well. It will not work as it was initially designed.

There's nothing wrong with ABS systems, they can help in some situations. For the typical family sedan, its best to leave the car stock, through testing and analysis, they have been configured to work well. For most on these boards, rarely do people leave their car stock. These vehicles are race oriented cars whereas many take them to new levels of performance. The ABS systems are no longer designed to work for these setups now and can be a major hindrance in many ways.

For others who have slightly modified the cars, and their ABS system is no longer functional leaves the user with two choices, either fix a system that apparently is quite problematic (especially with these cars getting quite old...the OP's car is ~14 years old. This can be very costly to repair and quite aggravating. Replacing an EBCM or other troubleshooting can bring costs to 1000.00...on a car that resells for 4000.00. Another choice is to remove the ABS system giving yourself the ability to finally tune the braking system and never have to worry about troubleshooting or paying for future ABS repairs.