Help: Freightliner FLD CEL & Buzzer

I'm not a mechanic, but I once owned a '94 FLD with a Detroit; a low coolant level resulted in the yellow 'check engine' coming on, and red 'stop engine' after about 30 sec; at no time did the oil pressure warning (the red 'oil can' lamp) come on. The two in my truck were separate and unrelated.

What does your oil pressure gauge read when the oil lamp lights? I assume you've verified the oil level on the dipstick. It could be an engine oil pressure problem, an oil pressure sensor, the lead to the oil pressure sensor grounding out somewhere or it could be the electronics in the light bar itself.

 

I can't recall where the oil sensor was on my old 60 series; the Kysor light bar isn't built to be repaired, and can be expensive to replace (it contains warning and shutdown circuitry as well as controls for signal lights). With the age of the truck, you could be looking at a chafed spot in the wiring harness.

 

Did a quick google search; the oil pressure and temp sensors should be on the driver's side of the engine block, to the rear above the bell housing and below the engine lift bracket (if you have one)

 

It would seem to be a wiring issue if it happens when braking or turning, however I understood that an oil pressure fault would cause a shutdown; if the lights and buzzer are coming on for five minutes there is something wrong with your protection system. are you able to check ecm codes with your truck?

 

Sorry about delay.. hope things are going better for ya. No, OBD2 readers won't work with DDEC ECMs (or any Class 8 ECM that i know of). My old FLD had a diagnostic switch in the lower left knee panel that would allow me to read flash (blink) codes off the CEL/shutdown lights. I would turn the ignition on, flip the diagnostic switch and the lights would flash sequences of codes with a pause between numbers. There is a thread in the Commercial truck 'garage' forum with links to many online sites that tell you what the codes mean and how to read them. The codes may be different for DDEC II/DDEC III ECMs.

Just wondering if your system was setting a fault code; if not, it might show a fault with the Kysor warning light bar as the ECM wasn't getting a 'low oil' signal.