locating a sensor warning

[shankos]

I have a two beep warning going off on a mercruiser 350 tow sport.

The items i have gauges for are engine temp, oil pressure and volts which are all reading ok.

The warning seems to go off some times then stop going off for a while then may start up again later.

In the manual I have found these items listed as possible 2 beep/min warnings for the 555 ecm engine system.

-engine coolant temp circuit hi/low
-electronic spark timing
-fuel injector wire open
-iac output hi/low
-knock sensor hi/low
-map sensor hi/low
-oil PSI circuit
-sea pump circuit hi/low
-TPS 1 circuit hi/low
-5 Volt Direct Current PWR Low
-Manifold Air Temperature sensor hi/low
-Shift Switch

I do not have a scan tool. Is it possible to somehow locate each sensor and determine which one is making the alarm go off.

If so how would you test for the sensor in question ?

 

[fat fanny]

Re: locating a sensor warning

I would imagine with not knowing location of the censors the first step would to be buying a service manual for your rig preferably Merc and not clymers and or seloc. Or find the audible buzzer (alarm ) it's self and trace all the wire colors back to the main harness and go from there. You will find that if your going to work on your own rig the manual is a must and is very educational and will save you loads of cash.

 

[shankos]

Re: locating a sensor warning

I have a copy of the service manual and the sensor locations. That is how i got a list of the possible sensors that could be causing the 2 beep warning.


my question was more to do with locating where the warning was coming from not where the sensors are.

I dont have a scan tool to tell me the sensor giving me the warning therefore i was thinking of trying to determine a method of testing each sensor one by one to determine the sensor giving me the warning.

The method of locating a sensor giving a warning was what i was trying to determine if there was a method for this.

Can i pull the sensor from the circuit possibly one by one to locate the warning.

 

[shankos]

Re: locating a sensor warning

no suggestions on how to isolate a sensor to find which one is giving a warning ?

 

[Don S]

Re: locating a sensor warning

Just follow the instructions in the service manual for checking each sensor. Problem is, they may test good with an ohm meter, but still fail when in use. That is what the scan tool finds while the engine is running.
Sometimes (Most of the time with EFI) you just need the proper tools and procedures. In automotive everyone sells scanners for engine, not so in marine.