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in2trux · 11-13-2018, **(Subject: Low coolant alarm )**

I'm about at wits end with this.
It gave me a problem a few months back. After removing the plug and cleaning it went away.

Since it came back I've replaced the sensor in the surge tank, the plug and pigtail, chased the wires back several feet inspecting for damage or fatigue, short of main harness that plugs into the ECM.

The old sensor only had two wires with one blank pin. The new sensor has three wires as well as the plug. I matched the wires to the old plug plus have tried every other combination.
My guess is this is this is part revision for later models.

My understanding is this is a 5 volt circuit but is showing 4.6 volts on Insite.
Coolant level is rock steady and never low.

Is there another sensor that could be causing this problem?
Any help or suggestions greatly appreciated.

Chamberpains · 11-13-2018, **(Subject: Low coolant alarm )**

Is it logging a code in the ECM or is it just the alarm in the dash? Could it be faulty truck side parts and not the engine side?

in2trux · 11-13-2018, **(Subject: Low coolant alarm )**

I'll have to get the code. showing 1 triangle, low coolant.
It's been so long since I've had any issues and no need for Insite
Temp is normal, MPG is 7-7.5

TBEV · 12-04-2018, **(Subject: Low coolant alarm )**

I have the same alarm going off in my Pete 386. was told it's a common problem. I replaced the tank, the sensor is built in, only way to get it, with the tank below, and the alarm went from sounding every hour or so to being on every second the ignition is on. When I find the solution I'll share.

https://amzn.to/2WpghAA

snailexpress · 12-04-2018, **(Subject: Low coolant alarm )**

(11-13-2018 )in2trux Wrote: I'll have to get the code. showing 1 triangle, low coolant.
It's been so long since I've had any issues and no need for Insite
Temp is normal, MPG is 7-7.5

Too sleepy to look where it was posted by Cummins. Bad coolant can set false signal.

dhirocz · 12-04-2018, **(Subject: Low coolant alarm )**

I tried everything on mine...new sensor and module, check the inside of the surge tank with a boroscope, checked the ground and 5 volt reference and resistance checked the wires, etc...

I put coolant in an inch above the full mark. Mine is no longer nearly that sensitive...hardly gives me an issue now.

Chamberpains · 12-04-2018, **(Subject: Low coolant alarm )**

Have any of you guys monitored the voltage of the sensor using Insite. Have you caught a voltage drop or spike that's happening at the same time the code or warning light is triggered. I noticed the OP said he only traced the wiring back several feet. Not all the way. The break or corrosion or bad piece of wire can be any where. Also, this sounds a lot like the problems with the TPS circuits. If it's a 5 volt circuit then it can be the slightest of bad pieces of wiring. If I were you guys, I'd have that whole harness out and probably just replace every inch of wire in it just so I knew it was not causing my problem. Sometimes wire go bad under perfectly good looking insulation.