Mercruíser 8.1 Horizon error code 3 Blk Psi Lo

[Davy Crocket]

I have a pair of Mercruiser 8.1 engines in a 2007 Searay. Both engines are giving a error code 3 Blk psi Lo and going into guardian mode. I cleaned all waterways, and the engines are running cool. Impellers are good and good water flow from theexhaust. This error only came up after servicing the cool pumps which were clogged and dirty.

Any ideas on a cause and solution?

 

[Docksidemarineservices]

The sensors are known to fail. Are they in the pump or the Power steering cooler? Check the three wire plug on the sensor for corrosion.