A family member owns a a 2010 GS350 that has a CEL and Traction Control lights lit up on the dash. He checked the gas cap and said it wasnt on when he opened the gas door (cap fell out). He screwed it back on but lights are still on. He took to auto store to get scan codes and it came back with P0455 and C1201. They told him may need a new gas cap.

1) Do the lights not auto reset if the problem is fixed?
2) If not, how does he reset the lights without disconnecting battery?
3) Is it common for a gas cap to just come loose/fall off like that? I looked at it and it can be tightened to the click but never heard of one just coming loose on its own.
4) If he disconnects battery to reset the light, any idea on how long before it will come back on if it isnt the gas cap?

TIA!

 

Many codes will be reset after a few drive cycles, if the problem has been corrected. You can also disconnect the battery, or use a OBDII scanner to clear the codes.

I suspect your family member didn't want to admit he/she didn't tighten the gas cap. If it's a non damaged OEM cap and installed correctly, it will not come loose and fall off. If you tighten it until it clicks, it shouldn't come loose and fall off.