Smart Craft beeps and says Check Engine

[ZL1]

Is beeps twice like every 2 minutes and if i try to drive faster like 25 knots it gives Guardian mode and says reduce throtle until i drop to around 2500-3000rpm.

engine runs fine on idle and on higher rpms. Pressures ok and temporatures ok. Changed impeller and added plenty of fresh gas after winter but no help...

What could be the reason...

boat is 2006 sundancer 260da closed cooling, bravo 3, mercruiser 350 mag mpi horizon.

 

[Dave S]

Deleted

 

[ZL1]

Now t has been checked with a scanner. There were 2 active fault codes. First was low battery or volts etc so the mercruiser mechanic said i shoul replase both batteries. He said these engines are really demanding on good batteries since they consume so much current due to 12 sensors active all the time. Second code was tpi 1 sensor. I think that must mean tps sensor. The mechanic said i should first see if new batteries will be enough if not then change also the sensor. New batteries ordered...

comments?