Intermittent alarm

EVolutionEVS

Recruit
Joined
Jun 8, 2020
Messages
3
2011 mercury 305 MPI sterndrive, excellent condition. all guages: battery volt, oil pressure, engine temp = normal
while running, i get an intermittent alarm that sounds for about 2 sec and stops. it happen about every 3 min or so, it is independent of any speed, rpm, etc. i have checked the outdrive lube reservoice. pumped out the liquiq so i can see the float. put a continuity meter on the wires and the switch closes on the float down (empty) and opens on float up.

i have discounntedd both float sensor wires from th circuit and no change in this behavior.

any suggestions ? mechanic friend says the alarm is either engine temp or the engine lub reservoir..
 

EVolutionEVS

Recruit
Joined
Jun 8, 2020
Messages
3
thanks. i will check into this. do you think a diagnostic tool would tell me absolutely what is causing the alarm
 

Searay205

Chief Petty Officer
Joined
May 27, 2018
Messages
471
Probably loose muffler bearings or i have seen bow light cause alarms. replace those also.
What engine is it, does it have catalyst? Probably being 2011. A Rinda tool would tell you the code but if catalyst I am 99% positive its one of your post cat oxygen sensors. Again scan tool would tell you. any chance you live in the Houston area?
 

Searay205

Chief Petty Officer
Joined
May 27, 2018
Messages
471
If you have PCM09 which is catalyst there are 100? items than can cause alarm. If you have PCM55 then lube oil level, engine temp, or oil pressure.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
thanks. i will check into this. do you think a diagnostic tool would tell me absolutely what is causing the alarm

Your alarm is a Guardian alarm. The ECU has detected something it's not happy with. It could be just a sensor (the ECU sensors for temperature, oil pressure etc are not the same ones as for the gauges). Or it could be a real condition. Being a Guardian alarm, the ECU should set a fault code, so yes, the diagnosis software should show what's going on.

Chris....
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
You'll need the Merc specific software. Standard OBD does not work..
 
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