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+--- Thread: Low coolant alarm (/showthread.php?tid=9988)
Low coolant alarm - 870 for life - 02-26-2025
Been looking around on the site but I cant find what I'm looking for so.
I have a 05 Volvo VNL CM870. I got a low coolant light and buzzer today. Expansion tank is full. I unplugged the tank sensor and still have the stop engine light. I then jumped the 2 wires going to the sensor and still have the stop engine light. Is the sensor just a NC switch or something different. I have been reading about a magnet but not sure if its the sensor that have. Not sure how it works yet. Haven't checked for voltage or ground yet. Just got home and its late. Anyone know how this works so I can fix my latest issue. Tank is 3 months old (aftermarket). I have schematics. Thanks for all your help
RE: Low coolant alarm - stevesparts - 02-26-2025
Just replace the coolant sensor. they go bad at times I've had 1 that just read bad at times. turn a corner it go off hit a bump gos off. tank was full, very frustrating, replaced it and the problem stopped also check you wires for and spots that might have rubbed through/pinched. that will kick it off too.
RE: Low coolant alarm - Rawze - 02-26-2025
STOP TRYING TO FOOL THE DA$MN SENSOR!!!!...
BUY AN OEM TANK!!!.
I CANNOT TELL YOU HOW MANY TIMES THAT I HAVE SEEN PEOPLE BYPASS THAT COOLANT LOW ALARM ... ONLY FOR A FEW YEARS LATER TO END UP ON THE SIDE OF THE ROAD WITH A LOCKED UP, DESTROYED ENGINE BECAUSE IT RAN OUT OF COOLANT DUE TO AN UNFORSEEN LEAK, AND DID NOT SHUT DOWN BEFORE ALL THE DESTRUCTION!.
RE: Low coolant alarm - J_Rok - 02-26-2025
If you can pull the sensor out of the reservoir and no coolant comes out odds are you have the magnet style sensor. With the sensor pulled out of the reservoir but wiring connected put a magnet near the sensor if the light goes out you need a new tank. If the light stays on you need a new sensor or have a wiring issue. If you have to start digging into the wiring I’d suggest getting a free quickserve account it’ll save you loads of time in finding the correct pins on the ecm harness.
RE: Low coolant alarm - marek4792 - 02-26-2025
Just swap the tank, even the Automann aftermarket ones for the Volvo's work fine if OEM can't be obtained.. Don't d*ck around with it or your pocketbook will be in a world of hurt..