Low coolant level message

Ryan0214 · December 29, 2019

I drive a 2009 Silverado 1500 LTZ 5.3L

A few weeks ago my low coolant message came on when I started the truck up. Coolant level was low, found the water pump to be leaking. I topped the coolant level before doing any repairs because I wasn’t able to fix it right away, low coolant message still came up.

I replaced water pump, thermostat, and both radiator hoses with new worm clamps. Filled the system, burped and topped off again. Low coolant message still comes on. I have not been able to locate a coolant level sensor, I pulled the surge tank out and there is no sensor, no wires running to the tank. Does not appear to be a sensor anywhere on the radiator.

I went to my local dealer and asked the parts guy to look up the sensor to see if he could find it, he said the system didn’t pull anything up at all for my truck.

I am stumped, any help would be appreciated.

Brian715 · December 29, 2019

Odd. My 06 has a sensor in the tank. But 09 is the next body style.

Ryan0214 · January 5, 2020

Bump

Ryan0214 · July 19, 2020

Bump

still curious, message has been on for 8 months

davester · July 19, 2020

I also have an earlier truck, so can't tell you where the sensor might be for yours. I would suggest signing up for the full-service manual at a site like alldatadiy.com . That will have the diagnostic procedure for finding where the problem is and how to fix it.

Ryan0214 · July 19, 2020

1 hour ago, davester said:

I also have an earlier truck, so can't tell you where the sensor might be for yours. I would suggest signing up for the full-service manual at a site like alldatadiy.com . That will have the diagnostic procedure for finding where the problem is and how to fix it.

I have all data and Mitchell at work, neither say anything about my truck. Shows for the diesels that they have a sensor in the surge tank, but my truck does not.

davester · July 19, 2020

In that case, I can see two possibilities

a) your truck has a swapped computer or a computer that's been flashed with the wrong code

b) the pin on the computer for the low coolant sensor, which isn't connected to a sensor, is somehow getting power or ground now, generating that message

I would first check b, perhaps going through the diesel wiring diagram to see where the low coolant signal goes on, and then comparing it with the gas version (what that pin is being used for), and checking your truck to see that pin/wire.