2003 Merc 496 MAG/BRAVO 1X
What does one look at when you get this fault code:

Port Clnt Overheat: 0
Starboard Clnt Overheat: 229 <-----?

Ran through allot of lake debris over the week end and then alarms went off.

Thank you

that means starboard engine coolant overheated at 229 degrees. Probably clogged your raw water intake and burnt up impeller in water pump. you need to change impeller at a minimum and you should also check and flush all coolers on engine in case impeller disintegrated and/or other debris made its way through the cooling system.

If you have a sea strainer, open that also and clean it out. If you don't, you should strongly consider adding one.

Coolant not Sea Water (lake Water) correct ???
Thank you, so now the obvious question.......where do you start to look. Sea Pump rebuild already underway.

How many hours on the motor? I'm not positive but I think the 229 means that it occurred at 229 hours. List the whole report if you can. I noticed the "lake temp" always said something like 461*, I don't think there is anyway the motor can read that temp.

is your code from the smartcraft gauge or from using the diacom scan tool ???


Guys here is the true meaning of the code.

it means Starboard exhaust manifold coolant temp overheat AT 229 DEGREES
and the port side should not be be a zero reading either.



More info about sensors and scans - Yes all ECM 555 and PCM 555 can read the lake water temps if the correct sensor is installed also they can read outside air temps as well. My 496 reads air temp cause it has the sensor for it. I can read it on the smartcraft gauge.

Here I will explain the lake temp crazy readings - IT DEFAULTS to its value cause it does not have the paddle wheel with the temp sensor it installed into the mix. It does have the option to do so but most do not come that way. Merc jet drive opitmax engine set ups have the lake water temp reading because they came with the paddle wheel and temps senspr combo installed on the transom of the hull. The paddle wheel reads MPH.

If you have the temp sensor / paddle wheel combo then it will read lake water temp. Without it it defaults to its highest value.

This holds true for all sensor that are not applicable / installed in the system. Its that simple.

Example Pitot is another good one that shows up in most scans why because there is no Pitot sensor installed in that application for it to read in the mix. So it defaults and shows a fault code for it.