Hello. I'm starting to have an issue with my 2001 ES 300 with 120000 miles. Recently the TRAC OFF light and check engine light pops up randomly. 2 times so far. The first time it came up I went to auto store and got a code scan and it said it was my gas cap so I got a new cap and the light still stayed on. So the only way to turn the check engine light and TRAC OFF lights off, I disconnect the battery and reconnect it. That lasted about 3 weeks and the TRAC OFF/Check engine came back on today in a parking lot out of no wear, and I did the same thing, I disconnect and reconnect battery and lights are off. The only thing I have been doing different recently was switch from Regular gas to Shell V-Power® NiTRO+ Premium Gasoline. I'm not sure if that could cause this but its the only thing I have changed in my cars regular routine in the past 2 months. My main concerns are safety, will I be safe driving in the rain and the on the terrible roads in Rhode Island and Massachusetts?
Any feedback will be appreciated.
Thanks,
401Driver

Need to know the stored code(s). Don't keep disconnecting the battery that will slow down the diagnosis.

Hello,

Most of the codes that trigger Check Engine light in ES300 will also trigger Traction Control. You need to understand that your issue is most likely not related to the Traction Control, but rather to some engine malfunction. I would suggest you to visit any local parts store and ask them to scan DTC codes, they usually do it for free. Without that, it will be excruciatingly difficult to find the root of your problem.

Also, by disconnecting the battery, you are erasing all the trouble codes stored in the ECU, which is a bad idea, since there is a reason for the CEL to trigger. Before going to the parts store, make sure that the Check Engine light is on, otherwise, you won't see any codes.

Hope this help and best of luck!

The day I got a scan at Autozone, I got the codes
P0441 Evaporative Emission System Incorrect Purge Flow
P0440 Evaporative Emission System
P0446 Evaporative Emission System System Vent Control Circuit

The paper also said at the top, ASE certified Master Technicians have seen this issues on your type of vehicle and the most likely solution is: Inspect for loose Fuel Cap and Tighten or Replace as Necessary, which I did that day i got the scan and the light did not shut off until i reset the battery.

This issue does seem quite similar to one of the earlier posts, although not as severe. The cap may have introduced the leak in the system, and since it is cheap and easy fix, you were suggested to try it. I would suggest inspecting your charcoal canister and all the hoses around it, if you won't see anything out of the ordinary, you should probably visit a specialist that will be able to perform an EVAP system diagnostics.

Hope this helps and best of luck!

Just FYI, I've had this exact issue for years on the same mode (though I get P0440, P0442, and P0446)l. After a smoke test and a lot of money replacing the charcoal canister and such, it was decided that the control board was likely faulty. You might want to consult with some folks as to if it's worth fixing before spending the money, otherwise a cheap OBDII reader with phone app can clear the codes for you, and you can just get on with your life.

Thank you and everyone else for contributing. The light went on again today for no reason, did not run over pothole or anything just poped on and I did the same thing i did last time, disconnect/connect battery.
I will be logging when this happens on this thread so I can count the days its off for and maybe we can see a pattern in the number of days it stays off/goes on. Also to help anyone having this issue as well in the future.
As of today, Its been 13 Days basicly 2 weeks its been off.
Upate it happen again on 8/7

The problem is that it doesn't matter how many times you will erase those codes, the reason why they are appearing will not go anywhere. When the car shows errors, it also takes them into consideration, changing its behavior in accordance to the situation. Each time you are erasing those codes, the issue stays there, and the car cannot adjust to the situation until it will trigger those codes again.

In short, you need to find the source of the problem, otherwise those codes will never leave. I recently found an official Toyota Service Bulletin that tells what needs to be done if all three of those codes appear altogether. it basically tells to check Canister Closed Valve located on the intake air box - connect 12V directly to it to see if it is working at all, and then check if the hose that comes to it is in good shape.

If all that's good, check EVAP Vent Control Valve, located under the car, on the charcoal canister, the process if the same as for the previous valve. While doing so, see if everything is good with the charcoal canister itself and the hoses around it. If none of that will help, visit a specialized shop that will test your EVAP system for leaks.

Hope this helps and best of luck!

Thanks for the info