Ok, I've read recently (through searching ) that I'm not the only one having this false add coolant buzzer going off.

I have done the following fixes:

NEW Mazda OEM Radiator Cap.
Flushed coolant and added new 50/50 mix.
Taken out sensor and sanded it (It was perfectly clean to begin with)
Replaced the "standard" Male to femal connector on the sensor by soldering the 2 wires together.

Still goes off randomly.

There IS coolant there. When I take the sensor off, its soaked in coolant (even when cold)...

Only thing I have yet to do is actually replace the sensor. Since it only has ONE wire coming off, and no where to actually get ground... I see now way of testing this thing.

Anybody care to fill me in?

Thanks,
Jon



S5 89 GTU.

 

It should be grounding itself to the body.

 

The entire plug is rubber coated. Only the probe at the end is metal, which I'm assuming goes to the single wire exiting the top.

 

It grounds to the coolant. (water=conductive)
If it doesn't get a ground, then there is no coolant around it.
So when the circuit/ground is broken, the buzzer and light goes off.
This means that simply you have a break in the wire somewhere between the CPU and the sensor, and it looses continuity at random.
Replace the wire, or run a new one thruogh the stock grommet. Not hard.

 

That explains it very well

Never thought about it actually grounding through the water.

You mentioned replacing the wire.... all the way to the ECU?
The wire goes into a big bundle of wires... and to me that looks intimidating as I KNOW I'll fudge something up in the process. Any recommendations?

 

run a new wire over it.