I'm getting a fault message on my mercruiser scan tool and it reads, "Pitot ckt lo" What does this fault pertain to? I'm thinking the drive oil reservoir being low. My warning alarm sounds after running over 3500 rpm for a while and motor goes into guardian mode "loses power". I thought the engine was overheating, but the guage reads 180 and I was told that's not overheating on a 496 ho, more like 200+. I would appreciate any input on why the engine warning is sounding and loses power. Is 180 overheating? If the drive reservoir was low, wouldn't I be alerted as soon as the key was turned or could it alert after running fairly hard for a while? I'm at a loss. I still think it's borderline overheating. Looked inside heat exchanger and several holes look plugged. HELP???

One engine runs about 160-165 deg. and other high 170's-180.

Check with a dealer, but it sounds like you've got some kind of blockage. Check your intakes for weeds and sand

I always have "pitot ckt lo" as well as "steer ckt hi" codes active, running or not. I assume they have something to do with sensors that I don't have installed. There is an actual code called "low drive lube". You need to get into your code history for it to tell you what is going on. Could be any number of things, I would hate to guess.

Its your water pressure sensor. It can be activated by small blockage in or near your intake on the lower unit or weak water pump. If your temp it fine and all is running well, the warning has to be cleared out by a tech either through his laptop (DDT) or if you are running Smart Gauge series, they can reset the system through the gauge.

Harper, there are numerous codes that come up for systems not activated. But they will not put them in the guardian mode. This one, I believe is for a speedometer option, that is not used very much. I believe Sonicboom is correct about the water press being the cause of the problems. If so you should have also had a " Sea Pump PSI Lo " fault with the scan tool. This fault will generally put you in the guardian mode and reduces available power to 6- 100% per the manual, but my experience has been in the 80-90% range. With the problems I had.

If the sensor itself is bad you should get a " Sea Pump CKT Hi, or Lo fault. The difference would be the Sea pump Press fault should give you a constant warning alarm, that resets when you drop the RPM to 1100-1200 RPM. The sensor fault should give you a 2 beep per minute warning.

My guess is a water pressure problem. Although your temperatures appear to be acceptable, 180 is a little high. This is about what I was experiencing, when I had this problem. As it turned out, my water pumps were shot after 60 hours. The pump housings are brass, and tend to erode in a short period of time, if you run the boat in muddy gritty water such as the Ohio river were we are. If you are lucky it may just need impellers.

My guess is a water pressure problem. Although your temperatures appear to be acceptable, 180 is a little high. This is about what I was experiencing, when I had this problem. As it turned out, my water pumps were shot after 60 hours. The pump housings are brass, and tend to erode in a short period of time, if you run the boat in muddy gritty water such as the Ohio river were we are. If you are lucky it may just need impellers.[/QUOTE]


Correct on temp, it should be lower. My experience is mostly with O/B but our I/O run the same Smart Craft gauges. Pending hours on impellars, every season is a good insurance policy to change them especially in mirky waters.

Pito Tube. Speedometer. Pressure is low because you obviously don't have one. I put gauges right on the engine at the oil filter for pressure and temp and on the intake for water, If i get a strange reading I open the hatch and read it direct. Never have they been wrong, the gauges are always off.

After plugged diagnostic computer in I get a reading with error code pitot pressure circuit does anyone know what this may be. When engine revs hits approximately 3000rpm its wants to shutdown.

As mentioned above, pitot is for a speedometer pickup tube. You likely don't have one and it wouldn't cause your shutdown

what engine do you have?