P1491 problem code

1999 Plymouth Grand Voyager 3.3, 200K miles with rebuilt engine.
Shortly after filling with gas the Service Engine Soon light came on. Autozone confirmed the code as P1491 Radiator Fan Relay Circuit. However, the fans are working fine in 103F weather, the gas cap is tight. The Fan relay was replaced about 2 years ago and have had no problems, temp guage stays at same place always. Blower for cabin heat & A/C can be eratic but a slight tap with a hammer on the fan casing usually brings it up to the proper speed and it will work fine for 4/8 weeks - could this be causing the code? I know I can shut out the light by removing the neg. battery cable for a minute or so, but am I ignoring a problem that may not be noticable right now?

Is there also a Check Engine light on this model? If so I'm inclined to think that it's just a programed event to get me to go to a dealership.

HVAC blower cause P1491? No. Completely unrelated. The "check engine" light is your SES light. Not a programmed event.

Reset the code by disconnecting the battery. May be a fluke. Check the rad relay connection for corrosion etc. Make sure your fans aren't binding.