My wife's 03 v6 2wd 4runner keeps having issues with the vsc and trac light going off. About 6 months ago the light came on and the car beeped at us. 10 mins later the abs system took over the front left then right and it was hard to control the truck.

I took it to a reputable indy toyota/lexus shop and he said no codes besides yaw sensor lost calibration. He recalibrated yaw sensor and car was great for 3 months.

About 3 months ago vsc and trac light came on again with 5 secs of audible beeping. I slowed and limped home then to the indy shop again. I got the same results that the sensor lost calibration. He reset and on we went.

Yesterday the lights came on again. I have now unplugged the abs pump so it cant take over the car until I figure out whats best to do. I pulled out the yaw sensor and inspected the wires and everything looked great. I am thinking about trying a used yaw sensor then have the zero point calibration done again.

Any ideas? Im at a loss of what to do. Dont want to resort to the dealer yet but I may have to...

TIA

Have your battery tested, I have a feeling the voltage is dropping too low. This is a known issue with '03 & '04 4Runners that Toyota has a warning prompt on the scan tool to tell you to either run the vehicle or hook to a charger when using the scan tool for extended periods of time.

The voltage doesn't have to drop so low the car can't start, just enough that is below "normal threshold." I would first start with the 12v Battery and then continue diagnostics from there should the issue continue.

Great idea. I went and replaced the battery earlier today. The battery had died on us a few months ago after having the doors open for only 30 minutes. I guess I should have mentioned I had a hunch that a power problem could have been an issue. The last time when my car through the VSC and Trac light I happened to be plugging in my phone to the charger that was already in the lighter. After thinking about it more, I think the first time this ever happened with the car I was messing with my phone too.

As stated above I have just replaced the battery and performed the zero point calibration myself. I test drove the car for 3 to 4 miles and everything was great. I decided to plug in my phone to the car charger. The charger into the cigarette lighter first(the one without the spring loaded cover)and it caused no issues. Once I connected my phone into the charger it beeped and the lights came back on. Does anyone have a wiring diagram or know if the lighter and the YAW sensor are connected on the same circuit.

Huh, now THAT is interesting... I'll see if I can dig up the wiring diagram for you a little later today.

Thanks!

I am thinking they must somehow be tied together. I was telling my wife I could just run new wires from an unused slot in the fuse panel by the driver left knee and that way she could still charge her phone and be safe. It just bothers me knowing something would possibly still go wrong.

I'm going to give you the overall wiring diagram, I have a feeling the "isolated" (i.e. Brake wiring ONLY, Engine wiring ONLY) might miss one or two cricuits that may overlap.

Here ya go.
Overall_EWD.pdf

Ummm...

You lost me at hello! I hate to ask for more of your help bc you've been great but....

On a serious note I'm not very good at reading wiring diagrams.

LoL, understandable. They can be difficult to read. I PM'd you some specifc pages to look at and to check a couple fuses regarding IGN, ACC, ect. I also think I may have found a TSB similar to your condition, but I PM'd you the information I need to reference that.

My steering shaft to the Rack came off and was not put back on straight. I adjusted the steering wheel to be straight and then had to pull the battery post off for a few seconds then it was fine.