Check engine, Trac, 4wd lo light on

Got gas and after driving all these lights came on. I assume it was gas cap . Only thing I did and no open doors. Disconnected negative cable for couple of minutes reflashing the computer and it went away. Otherwise I have no idea except I didn't have to buy anything. Rear hatch not shut caused similar situation before.

 

Well not sure what you are asking but if it cleared what can you do?

 

Well I read and hear a lot about this happening and I was passing on my experience without running to dealer. It's the most technical 4runner I have owned and I have to learn along with everyone else.

 

Leak at fuel cap should cause the the check engine light to illuminate at the second startup after fueling. If the light came on at any other time the culprit could be elsewhere.

 

Yep. Did it again this morning after second start up. Reflashed ECU and been fine. Seems to happen more after running tank really low and fueling. Cap doesn't click and not sure if it is supposed to. I know it did on other vehicles.

 

^Fuel cap is supposed to click, either once or 3 times depending on design. Replace the fuel cap first - cheapest thing to try.

It's also possible you have a small evap leak elsewhere in the system. The charcoal canister sits low on 4Runners, just above the spare tire, so it's exposed to a lot of road grime. I had to replace a couple of clamps on an evap hose when I noticed the factory clamps were rotted off.

 

CEL will keep showing up if there is a problem somewhere. Connect a scanner to see what codes it is throwing. It should have a few 'pending' codes.
If it's an EVAP code, the CEL will normally show up after 2 cycles , which would be a few days after you clear them.
Easiest to start is to get a new OEM cap. Do you have a tendency to 'Top Up' every time you fill gas?

 

Well I also replaced the foam filter on evap pump with state of the art Chinese Kay/ Inn filter and knowing better. I think I will replace with original and replace gas cap. Actually seems to happen when I run tank closer to empty and fill up. I usually don't go below half to ease the pain at pump. I might find a junk yard cap to try before going all in on new Toyota.

 

I just replaced my 12’ Sequoia cap with a OEM cap. It was less than $20 from the dealership.

 

Evap pump? I hope you don't mean the manifold air injection pump under the hood? That one has nothing to do with the evap system.

 

"Re-flashed" ECU? You used Techstream or similiar to remove, and reinstall the entire complete ECU software with updated calibrations? Because this is what reflashing a module entails.

Or you disconnected the battery cable and cleared the temporary memory so the CEL and dash warning telltales disappeared?

If rear hatch not being shut caused this issue before, I would check to see if your battery has become marginal. When B+ voltage drops below 12v, it can cause all kinds of silly issues with sensitive modules. Check battery voltage with a multimeter before starting the vehicle, after setting overnight. It its less than 12.2v or so, its time to open that wallet.

 

Not actually reflashing, resetting I guess.

 

It was gas cap. I got one at parts store and it fixed it. Have Toyota cap standing by. Tired of resetting radio.