Yesterday during track day at Thompson, "Service Advance Track" and the ABS and Advance Track lights came on; in addition to the Traction Control Off light which was already on because I had turned advance track off.

This happened twice; both after about 30 minutes on track. The rear brakes were good and hot, probably hotter than the front. (judging by feel, need to get a thermometer, and no I didn't actually touch the brakes, that would result in a nasty burn)

I pulled off track and shut the car off and let the brakes cool a bit; then when I restarted the car the lights were still on; then after driving a short distance (like less than 100 yards) they would go out. The exact same scenario happened twice.

The first time I was not 100% positive I had turned advance track off . . . though I was pretty sure, because I normally do turn it off. The second time I was positive that I had turned it off before the session. (full off, not sport mode). The last session of the day it did not happen.

It seems like the rear brakes are getting hot and somehow tripping the warning or messing up the sensors?

I did try a couple quick searches and I find threads that talk about the Service Advancetrack lights, and about the rear brakes getting hot, but not the two together like this.

Thoughts / suggestions?

 

2 likely causes:

1) Overheating of (probably rear) brakes causing loss of wheel speed sensor signal. This would take take down ABS as well as Advance track

2) The ABS/TCS/ESP ecu could have overheated as well which would put it in thermal protection or passive state.

First is more likely based on the fact that you had to drive for the system to recover. My money would be on Wheel speed sensor. Next time you have the wheels off look at the molded plastic tip near the tone ring, see if you can spot any damage. It's also good to clean it up and get rid of metallic dust since it is a magnetic sensor.

Also you can read the codes to confirm at autozone for example.

 

My money is on the wheel speed sensor as well!
Got too hot!

 

Thanks guys, I will take a look at that.

Also I have another idea what might be happening: I changed to DOT4 brake fluid last year (StopTech 660) and that should be fully flushed at least once a year. This spring I have flushed out the front reservoir and front brakes with new Motul RBF 600. But I haven't got to the rears yet. So maybe there is some moisture in the rear of the system and that is boiling when it gets real hot and that is messing up the advance track sensors? I didn't notice any real brake fade but the fronts are doing most of the work anyway.

Let me know if that makes any sense. Thanks again.

 

Hi Bert, good luck with diagnosing the issue. I don't think the fluid in that rear would give you anything else than reduced performance. The pressure sensor used for ABS/TCS/VDC control is in the master cylinder, not in individual brake circuits. And besides the hydraulic layout in our cars is X split, meaning one circuit is front left/rear right. So you flushed half of each circuit. The only active sensor in the rear for ABS/TCS/VDC control is the Wheel Speed Sensor, so that's your primary suspect.

 

Update: I'm still kinda frustrated by this, though I haven't really spent the time needed to diagnose it.

No, I haven't inspected or cleaned the sensors . . . the caliper and rotor have to come off to get at it, I haven't had time to do that. I can see that it is covered with crud, maybe cleaning it would help. But if it is damaged, I would expect it to give the error all the time, not "get better" when it is off track.

I did manage to find the time to flush the rear brake lines, though I didn't re-do the fronts, so there could still be some moisture in there, though I think you are right, that's probably not it.

I did another track night this past week, and it happened again. I can't say for sure if it is really affecting the way the car drives; but the car did get a bit squirly about the same time the warning came on (could be my gummy-bear tires melting) and it kinda kills my confidence so I pulled off the track.

Yes I am sure that I turned advancetrack completely off before entering the track.

The rear rotors were quite hot -- I saw 577 on my infra-red, which I think is its maximum (shouldn't have bought the cheap one) so it might have been hotter than that. This is after half-lap cool down and driving to the paddock, getting out of the car, rummaging around in my bin to find the infra-red, etc. Interestingly the front were not as hot, around 450 or so.

I checked for codes using my SCT tuner (DTC's as it calls them) and it said "no DTC's found." This was while the car was still in the error condition -- warnings still displayed on the dash. I repeated this several times to make sure I wasn't doing something wrong, with the same result -- "no DTC found"

Same as before, after a bit of a cooling off period and then moving the car a little, the warnings disappear. Apparently the computer is getting the signals it expects again so it is happy.

I have vacation this week so will finally have some time to work on it. I'm thinking I will up-size the rear rotors and remove the dust shields. Will look at the sensors while I'm in there. Also need to replace my pads which is another dilemma, I think I'll start another thread about that. I talked to a guy at Carbotech and he thinks maybe I am overheating my StopTech Street Performance pads; then requiring excessive pressure to get decent braking; and that could be triggering the warning. I think this is a stretch but you never know.

Any other thoughts?

 

For the ABS lamp to come on there can really only be 4 root causes:
1) Power loss to ESP module
2) Loss of master cylinder pressure sensor information
4) Loss of wheel speed sensor information
5) ECU/Micro internal error of the ESP module

I doubt it is 1 or 2 since it comes back. The ECU could overheat I suppose, but even then ABS would be OK. So I has to be loss of power, or temporary loss of WSS input

 

Yep, probably #4 . . . or is it #3? LOL . . .

So my planned mods to try to keep it cooler make sense. I just ordered the brackets from the guy on e-bay to move the calipers to fit the larger rotors without pulling the axle. About to order the rotors also . . . I am thinking of the slightly higher priced centrics, available on Rock Auto for $60/each (the cheap ones are $30/each but I figure it is worth the extra $60 total for the good rotors if I am going to all this trouble)

http://www.rockauto.com/en/moreinfo....504558&jsn=472

 

Ha, not sure what happened to #3. But hopefully that helps!

 

So I finally found the time to upsize the rear rotors.

While I had it all taken apart I checked the ABS sensor and the gear thing that it apparently senses -- the right side was really dirty; left was pretty dirty too . . . cleaned it all up. I was going to pull the sensor to really clean it, but it didn't want to come out after I removed the bolt on the back, so I skipped it for fear of breaking it.

Also while I was at it, I changed the pads to Carbotech XP10 in the front and XP8 in the rear. Man changing those rear pads is a pain in the but. The Brembos are a pleasure by comparison. I sanded the front rotors a bit to remove the old brake material; hope that will be OK.

I did take pics of the install and will post when I get a chance.

Track Night at Thompson tomorrow to test it out!

 

Good luck! let us know if that fixed the problem.

 

So this issue is still plaguing me. Last night it did it again, and I actually spun the car in a turn that I have taken hundreds of times pretty much the same way. It could have been driver error for sure; or I'm thinking the system applied the rear brakes and that caused (or helped cause) the spin. Luckily no impact and no damage, but very confidence un-inspiring.

I did (finally) find enough time to thoroughly go over the brakes. Replaced the rear rotors with the bigger GT500 ones (using very handy brackets purchased from a guy on e-bay) and replaced rear brake pads with Carbotech XP8. Cleaned the ABS sensors and "gear." They were fairly dirty but appear to be intact. Replaced front pads with Carbotech XP10. Bled/flushed the lines with Motul RBF 600.

First track session was fairly short, to bed the new brakes. Followed the Carbotech instructions (clarrified by Mike Jr. on the phone, thank you) and got them hot enough to fade, which indicates out-gassing of the new pads, then let them cool. Had a nice gray/blue layer of pad material on the rotors; but also had a very hot looking orange/blue stripe along the inner diameter of the rear rotors. Front rotors were about 450 and rears about 350 after a cool down lap and pulling into the paddock.

Second session, the warning lights came on after about 10 minutes or so, when everything is good and hot. It was a sunny day and the track was hot; tires get pretty greasy. I do get some understeer and tend to ride it through the corners a little; nothing major just on the edge with the front tires (and rear) singing a bit. Also I triggered the ABS lightly a couple times (new pads are a bit more agressive than I am used to) but did not ride the ABS much. When it came on I said to myself "awe crap, there it goes again . . . and the car is feeling squirly again too . . . " but decided to keep going. I think it was the following lap that I had the spin.

Third session, I took it easy and tried to stay out of the ABS and minimize the understeer. I did tickle the ABS once lightly. My pace was definitely off from what I have done in the past. (Lap timer was not working, stupid i-phone . . . . ) Made it through the session without the warnings and without incident. The sound and feel of the brakes did concern me a little after the main straight; not the squeel I was expecting but more of a hum/vibration; not sure if that is normal? (these are my first track pads)

On another forum, guys have suggested the system could be coming back on and/or going crazy over ABS events; excessive understeer; or excessive slip angles. I guess these are possible; like I said I did trigger the ABS a little and I do get some understeer. Derek you rode with me and you saw the understeer I am talking about.

So I'm kinda frustrated by this and would appreciate any suggestions or critiques . . . .thanks

 

Bert, sorry to hear your issues. You definitely have some sort of failure in ABS. Have you checked what code is set?

As for the pulsations, I thin you're experiencing brake chatter, or uneven transfer of material to the rotor. Carbotch pads are known for this. At low to mid force braking you can feel steering wheel vibrations, right? But at full braking it seems solid?

That's my experience with the XP10s.

 

Hi 5-dot, thanks for the quick reply . . . .

I tried reading the codes with my SCT tuner before, and got "no DTC's found" . . . did not try again yesterday.

I get the hum/steering wheel pulsations on fairly hard braking; I was trying to stay out of the ABS so not sure if I was getting "full braking" or not.

 

Bert,

your SCT will not display ABS codes. Get a reader that get's those (either IDS or some aftermarket ones). Once you have the code, it is so much easier to diagnose. I remember i used to have an Equus/Innova reader that did ABS codes.
Without the code, you can do whatever. I had a light breakage in a sensor cable once and if you turned the wheel too much to the right, the light came on. Codes make it a no-brainer to diagnose.

LEXiiON

 

Thanks LEXiiON, I did not realize that . . . I wonder if the local Advance Auto Parts free code reading service would get the code?

 

I believe Actron makes an OBD II scanner that reads ABS codes. I have one at home and I think it can, but I'd have to double check later.

 

I checked two local shops about scanning the codes, and the general concensus is that they are probably cleared by now. So it seems I need to get my own code reader and get the codes right away next time it happens. Which kinda sucks because I would like to fix the problem before my next track event, rather than suffering through another one like this.

So now I'm thinking I will get a Bluetooth ODBII reader and kill two birds with one stone -- be able to read the codes, and also transmit data to my track app (currently using Track Addict, might switch to Harry's in the future)

But having a hard time confirming that they can actually read the "body codes" aka "ABS codes" ; will have to do some more digging.

 

I think I finally found the problem!

The wire loom and some of the wires (from the right rear wheel speed sensor) were melted, up under the car where the wire runs over the axle, above the over-axle pipe. Apparently it only made contact with the exhaust under fairly extreme cornering.

I made a sloppy repair but it seems like it will work, I'll probably have the wiring harness replaced eventually. So far so good; hope it will hold up for the SCCA Time Trials next weekend.

See thread in the 2010-2014 section for more details.

Thanks again everyone for your suggestions earlier in this thread. The solution actually came from a user on a different board.

 

Sweet! Glad you found your wheel speed gremlin and were able to patch it!
Hope it holds up and you can do your next track day worry free.