zippinbye

Hi all,

Here's a new one to me: On the dash, the Brake light remains on with parking brake released. Fiddled with brake handle in an attempt to eliminate position sensor issue; does not seem to be the case (no way to extinguish the light even with extra downward or side to side pressure on brake handle). Brake fluid quantity verified good. No ABS light. But the trio of stability control lights are illuminated too (VSC TRAC/VSC OFF/Slip Indicator). Strangely, there is no CEL/MIL illuminated. Also, I just plugged in my AutoScanner CP9135 ( a fairly basic OBD II scanner). There are no stored DTCs. I also have an intermittent airbag light which has been showing up periodically for a few years; seems to crop up when the seasonal temperature down turn occurs - never seen it during summer. In this case, I am almost certain that the brake and VSC lights came on one day and the airbag came on later. Now, during daily driving, the 3 VSC lights sometimes extinguish, but the brake light is on to stay it looks like, and the airbag light is pretty steady too. Problem with the airbag caution is that it never remains on when I take it to my Toy/Lex Indy shop, and it leaves no trace on the OBD. So in my mind at this point, the airbag has no relationship to the new VSC and Brake light presence. I should also add that I have tried maneuvers that might call upon stability control and/or ABS, but just on pavement. As always, this rig will not do a burnout, even around a corner. Cannot achieve wheel lock-up under extreme braking. Attempted to drift on a wet street ... solid as a rock. Not sure I did anything extreme enough that VSC would have kicked-in if working properly. I guess I need to get into the dirt to discern that a bit more.

Trying to find something in achieved threads, I see no identical symptoms. But one common theme suggests the possibility of a wheel speed sensor, but again, I emphasize that no ABS lights have shown up and I cannot even produce a chirp from a tire while braking hard. It seems that a MIL almost always accompanies VSC lights in reports from other members, and in my previous experience.. My CEL has not as much as flickered. At this point a trip to the shop seems in order. But time constraints and vehicle requirements interfere and the GX continues to drive without a hint of diminished safety. Curiosity mounts in the mean time. So of course I would like to hear opinions about what other members think is going on.

Thanks for any thoughts you can share!

chiph9

Check the charging system (battery, alternator, and so on). Low voltage can cause strange errors in the computer. Look at the battery cables for bulges, weak points, and corrosion.

Try doing a reset - disconnect the negative terminal, wait a couple of minutes, then reconnect with a minimum of sparks. You'll have to set your radio stations, auto-windows, memory seats, and auto-sunroof saved settings afterwards.

Chip H.

zippinbye

Some of what I included in my thread-start post kept playing back in my mind .... I stated "brake fluid quantity verified good." Well, define good. My human eye discerned that the level was between minimum and maximum, but I got to thinking about positioning or calibration of the sensor that would detect low quantity. There is no visible fluid leak, so how could it be any less than any other time in the 7 our so years the GX has lived with us ? I've performed numerous pad/rotor services - never cracked a brake line. Well, I got to thinking that we recently had our Indy shop replace the brake fluid in September. So it's likely the fluid level could be different, perhaps lower than the preceding 7 years. And just maybe, a marginal fluid level could trigger a caution as our environmental conditions change from a very hot fall to a silly-mild winder introduction. We've gone from 100's and 90's to the 70's for daily highs, with some mornings touching the upper 40's. rather than fussing with the time and expense of getting to the shop, I swung by O' Reilly's for some brake fluid. I added perhaps 6 ounces to leave it just below max, and voila; problem solved!! There is still an airbag light - separate issue as I had thought. Brake light and all VSC cautions cleared. Sometimes you win

chiph9

Either they didn't fill it up like they should -- or you have a leak. Keep an eye on the garage floor for drips.

Chip H.

zippinbye

No evidence of a leak, anywhere. I'd say they did not fill the brake reservoir like you or I would have. I never had cause to inspect the level until an issue arose. Not surprising that a shop would take it above minimum and call it "good." They saved perhaps 8 oz. of fluid versus taking it to the max line, I'd guess. Another case in point argument for the ole' "if you want it done right, do it yourself" argument. However, this shop is known for generally good work and fair prices. This was the first time I've seen them skimp on something. I think it was around $100 for a brake fluid purge and fill. It might have cost me $20 in fluid to DIY, but I do not have a good system or plan for brake fluid recovery. So $70 worth of labor and shop overhead, roughly. Just my time alone, working at floor level in my garage, makes it a bargain in my mind. But I know I avoided making a mess, and dodged potential issues with a bleed port that might not re-seat properly. Sure it caused me a few days of concern and a drive for fluid, but BFD. I'm okay with it. The potential solutions ranged from hundreds to thousands of dollars and several days without the GX to stone-age simple, which is the way it went. Thanks for the suggestions!