Dash Alerts

My low-mileage 08 has recently been showing two icons on the dash periodically. They are the "Check Engine" icon along with the VSC icon. I've checked the vehicle and everything operates normally. I clear the dash by disconnecting the battery momentarily and everything's fine for a week or so, sometimes more, sometimes less. The icons seem to be unrelated and I've had a similar issue with my other car (not Toyota) with several unrelated alerts. Every time it seems to be battery-related...common with our late model cars it seems. The battery's almost new by the way on the 4Runner. ANY IDEAS??

 

VSC is often disabled by default whenever any type of cautionary alert is triggered. First thing to check for unexplained CEL with no other symptoms is the gas cap. If it’s no longer sealing properly, it will cause the CEL light.

 

Suggest scanning for codes on the next instance before you disconnect the battery to see what is stored. The light has a purpose and is your indicator that a code has been set.

 

+1 on scanning for codes.

 

Auto part store or cheap scanner will give you the aforementioned codes.

Keep in mind that whatever comes back is a symptom of your problem, and does not necessarily point to a direct cause.

The VSC light may or may not be directly related, so check engine light (CEL) first.

 

My 2008 did this a few weeks ago, i drove to work, parked that morning and was at work a long day. Cranked up that evening to go home and boom, lights on. It was late like 9-10pm and i couldnt drive it to town and get a reading from AutoZone so i checked it out and drove home cautiously. It still cranked and ran fine but the check engine and stability control lights were on. I went to AutoZone the next day and plugged it up and got the codes, it was a bunch of "possibilities" but the internets assessment of the code was that it has a wheel speed sensor going bad. I decided to just screw it and i kept driving it about a week with the lights on. One night it rained and on the way home i came around a stop sign and turned right and goosed the gas to spin the tires and the traction control ABS stuff kicked in. In case you havent ever heard it, it sounds like a jackhammer hitting your firewall and the computer pulls power practically cutting your power while the ABS system pulses the brakes to control the wheel speed to straighten out your skid.
When this happened the lights on the dash immediately went off. I said to myself "ah'ha" and i speculated the ABS system may have gotten an air bubble in them. My rear brakes are about worn out probably down to 15%, fronts are about 25% and i park on a slight hill at work. I'm kinda thinking my brake fluid is a bit low in the reservoir and maybe i got an air bubble in the system.

Believe it or not it did the same thing, cranked it up and both lights were on about 2-3 weeks later and that night i went out and spun out in gravel to force it to pulse the ABS system again and it fixed it again. I'm thinking the ABS system got an air bubble in it and when you force it to pulse it bleeds it out of the ABS module.

You could also have a wheel speed sensor going bad too but i would recommend taking a right turn and smashing the gas after you get a little rain to force a spin / skid which will trigger the ABS to kick in. This should clear the light if its like mine and maybe has an air bubble in it. If its actually a wheel speed sensor my trick likely wont do anything.