It also rained on my Gen 4 '17 maintenance project today. Like many of us I removed the air induction system on my older FJR. So why not remove it on the Gen 4 '17? Response: doing so caused the check engine light to come on or so I think.
Anyway today gravity was defied when the Three Bond 1215 held the valve cover gasket in place when I installed the valve cover. Yea!
Next was to button up the top end by installing the coolant tube, hoses, connectors and bits and pieces taking great care to do a good job because I have a habit of forgetting a bit or a piece from time to time.
Added coolant without spilling a drop, darn impressive, installed the fuel tank with connectors and fired up the FJR. Check engine light came on and stayed on. Decide to re-install the air induction system and so I did. Fired up the FJR and the check engine light came on and stayed on. Nuts.
I check for error codes in the FSM and find this on page 8-114. Seems on Gen 4 will cause the check engine light on if the air induction system is not present. Nuts.

Tomorrow I will button up the plastics and finish the work. Have not decided which way to go to clear the light. Maybe a short ride and it will clear itself but maybe not.