Mercruiser MPI fault 54 and 56

[alldodge]

Does the SW low pressure alarm still throw up gaurdian mode ?

Yes it does, it starts off with two beeps every so often (if beeper is working) and if rpm increases and pressure reduces it will go to guardian mode

 

[QBhoy]

Ok...thanks All dodge. No beeper since the IAC was replaced last week (perhaps it has broken after sustained beeps for hours on end on way home) defo fault code 3 showing at every use, even after clearing.
Wishing I had taken pressure sensor off now when I had the cap off today and was in about that area. Am I right in thinking it's at rear top end of engine ? Any idea on spanner size ? Looks about 27mm or perhaps imperial equivalent?
Local Merc guy reckons it's a common fault and can get crudded up when in shallow water (which I ha e been recently a fair bit.
Is there data for readings I could take to test or just clean it and see ?
Really appreciate your help through this total pain in the arse time I'm having AD !
Allan

 

[alldodge]

The seawater pump low is code 23
The sensor is located on the power steering cooler and in most cases its mounted across the top of the rear of the motor. I have the drawing for the sensor and it looks like 24 MM but not sure because its fuzzy.

This is what I have for the different ones in the series

 

[QBhoy]

Brilliant AllDodge. This is superb. Only thing is that in the manual I borrowed off the Merc dealer recently fault code 3 is SW pressure sensor. I've tried to attach pics.

 

[alldodge]

Well, I'm finding 23 with my older stuff, but Merc keeps changing things.

 

[QBhoy]

This is the latest. The boat seems to be running ok now but still running through fault codes sequentially.
Below is the latest screen shot. It says "sensor fault service engine" this is new. See screen shot

 

[alldodge]

Code 12 and 13 are hard faults, 12 low drive lube and 13 low oil pressure.

 

[QBhoy]

Thanks All dodge.
They aren't genuine faults. This is just and example of some of the faults shown. It literally counts right through the faults every time it's started in order sequentially.
It used to just list the fault code....now it lists the code and says sensor fault service engine soon. Crazy. I've emailed Mercury, but no response.
Thinking of just disconnecting vessel view and getting on with it.

 

[QBhoy]

Originally the faults were genuine with the IAC and Miss fire. A new IAC and cap/rotor solved this but ever since, the genuine faults it throws random non genuine ones at me. No beeper alarm. Gaurdian mode was active for a while too.

 

[QBhoy]

Wondering if the after market IAC is the issue ?

 

[alldodge]

Wondering if the after market IAC is the issue ?

Don't think that is the issue, many have used the aftermarket and none have had your issues. I'm at a loss

 

[QBhoy]

Me too !