I'm pretty sure this is normal since I verified it with a friend who has a 12V. When I start the truck, especially when it's cold enough to cycle the grid heaters, the "Check Gauges" light stays on for a few seconds longer than the other lights. Looks like it's on for 2 reasons, the Voltmeter is low (due to the heaters I'm sure) and the oil pressure gauge takes 15 sec or so to come up. Is this just because it takes a while to pump the oil up to the sending unit? Oil pressure hasn't been low like that any other time, I really don't think there's anything wrong with it, just kinda disturbing the first time I noticed it.

 

the oil pressure sending unit is not a true pressure transducer. all it needs to see is 5 pounds of pressure to tell the computer everything is running right. the oil pressure needle only works as a formula that calculates engine speed and vehicle speed to calculate where the needle will point. at 5 pounds if your pulling heavy up a hill you will fry the engine.

besides, mine does similar to what yours does when it is cold.