Diesel Engine Start Up Alarm

[philschwenk]

Tugnutters-
I have a 2012 Ranger Classic with a Yanmar diesel. After a recent cold snap here in the Pacific Northwest I wanted to start the engine and let it run for awhile. The alarm that always sounds when the key is switched to the on position did its usual thing but then wouldn't go off. In addition I got a "check engine" message on both the Garminn and the Yanmar display panels.
I checked the oil level which was fine and the coolant level which was a bit low. Topped off the coolant but on a re-try start the alarm kept blaring away. Salt water intake valve is in the open position so that's not the culprit.
Maybe the sensor itself is bad?

Any suggestions much appreciated.

Phil

 

[cal & pam]

I have a 2009 R25 Classic with the 4BY2 Yanmar diesel engine. Similar issue with the Check Engine alarm. The problem turned out to be a failed glow plug. This failure is not identified in the Yanmar Check Engine alarm display. The only way we found it was talking to an old Yanmar mechanic who, luckily, remembered this happening with older Yanmar engines. My glow plug failure happened during the summer, so was not temperature related. I believe that the glow plugs are only needed as an assist for low temperature starting. If that is true, you can run the engine, if necessary, without causing further harm. However, the check engine alarm is very annoying to listen to. Please let me know if this turns out to be your problem.
Cal

 

[knotflying]

This issue is not unique and has occurred on other Yanmar engines.
The issue is the glow plug sensor, on the port side of the engine. It is not really required for where we boat. I disconnect it it and never had an issue after that. I really can't remember exactly where it was. I believe it was near and below the ECU.
>

 

[philschwenk]

Thanks so much for the response fellow Tugnutters.

 

[scross]

Another common cause of Yanmar engine alarms is bad grounding between the ECU and the engine block. Oil pressure alarms are also frequently caused by a bad ground between the sensor and the engine block. There is a service bulletin for the oil pressure ground problem but not one that I’m aware of due to the ECU ground issue.

 

[GaylesFaerie]

I had identical symptoms in the summer that turned out to be a faulty water in fuel probe.

 

[DC3]

I have a 2012 R25sc and have same problem. Normally the alarm sounds until the engine is warm. To turn the alarm off you can press the first and forth buttons simultaneously on the Yanmar engine display. To display the error codes, hold down the fifth button until the menu is displayed. From the menu you navigate the check engine codes. I am taking my R25 to a Yanmar service center in the spring to resolve the glow plug issue.

 

[William Sanborn]

Replaced the house batteries, took photos of the cables and when done started the Engine and the Engine alarm would not stop. Took a while and lots of study of the photos to realize that the Alternator Cable on the house set had fallen down behind the battery and I had missed it.