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Can someone explain how the coolant level sensor works? I can't get mine to stop buzzing! (and no the coolant is not low.) I've searched and I've found two useful threads, but it sounds like they have conflicting information on how the sensor actually works.
The first thread I found indicates that when the sensor identifies coolant in the tank, it will send a voltage signal to the ECU. This make sense to me, as that is how most sensors work.
The second thread I found suggests grounding the signal wire to shut the buzzer off.
I may be confused, but how does grounding a signal wire stop the buzzer? Wouldn't grounding the wire cause the buzzer to go on as the ECU would no longer be receiving a signal?
I've already checked continuity in the engine harness and I made a jumper from the coolant sensor to the connection under the elbow just to double-check. I got a new sensor (I needed one anyway) and I still get the buzzer!
One last thing: I'm only getting the buzzer about 80%-90% of the time. Is it possible there is a short somewhere between the engine harness and the ECU? Does anybody know what pin this connects to in the ECU?
Anybody have any other ideas? Thanks in advance for any help.
The sensor acts like a normally open switch. when coolant is full electricity travels through the coolant to complete the circuit as the previous poster said. Since you got a new sensor installed there must be a bad connection somewhere or air in the system? Possinly your collant isnt conductive enough?
Thanks for the replies. I was out of town for the weekend and came to the same conclusion, that I have a break in the line somewhere between the connection under the elbow and the ECU.
Does anybody know what terminal the coolant sensor connects to in the ECU? I looked at the wiring diagram a little last week when I was troubleshooting, but I haven't gone through it all the way. Thanks
Thanks for the replies. I was out of town for the weekend and came to the same conclusion, that I have a break in the line somewhere between the connection under the elbow and the ECU.
Does anybody know what terminal the coolant sensor connects to in the ECU? I looked at the wiring diagram a little last week when I was troubleshooting, but I haven't gone through it all the way. Thanks
Did you ever get this resolved. I am dealing with the same issue. My sensor only comes on the first time I start the car if its been sitting. Once I am out and about it doesn't come back on. I made a jumper to ground the wire that goes to the sender but that didn't stop it. Though I now see from the other thread posted it takes 10-15 secs for this to work. Pretty sure I had it connected that long but will have to test it. I have a spare waterneck with another sensor so I may swap them to see if I can definitively rule out the sensor.
Did you ever get this resolved. I am dealing with the same issue. My sensor only comes on the first time I start the car if its been sitting. Once I am out and about it doesn't come back on. I made a jumper to ground the wire that goes to the sender but that didn't stop it. Though I now see from the other thread posted it takes 10-15 secs for this to work. Pretty sure I had it connected that long but will have to test it. I have a spare waterneck with another sensor so I may swap them to see if I can definitively rule out the sensor.
Your coolant might be ever so slightly low. so when the car sits, the coolant is under the sensor, but then with the added turbulance of coolant moving around the system it may then reach the sensor.
Your coolant might be ever so slightly low. so when the car sits, the coolant is under the sensor, but then with the added turbulance of coolant moving around the system it may then reach the sensor.
Sorry, I left out some details. My buzzer stays on at least 5 mins, I timed it once. When I check the coolant at the AST, its full. When I check at the water neck it is partially covering the pipe plug that is located above the sensor in my water neck (will try and add the pic). So I am 99% sure the sensor is covered in coolant when I start the car. Will triple check the next time I head out.
I serviced the entire cooling system in Feb. The car was new to me in Nov. New alum rad, new coolant hoses, thermostat, coolant, etc. It does not lose any coolant, or very little, over the last 1000 miles. Driven it on four 250mi trips in the last 4 months.
Sorry, I left out some details. My buzzer stays on at least 5 mins, I timed it once. When I check the coolant at the AST, its full. When I check at the water neck it is partially covering the pipe plug that is located above the sensor in my water neck (will try and add the pic). So I am 99% sure the sensor is covered in coolant when I start the car. Will triple check the next time I head out.
I serviced the entire cooling system in Feb. The car was new to me in Nov. New alum rad, new coolant hoses, thermostat, coolant, etc. It does not lose any coolant, or very little, over the last 1000 miles. Driven it on four 250mi trips in the last 4 months.
Your thermostat probably opens after about 5 mins or so, which may contribute to your problem somehow.
Maybe the coolant only goes above the sensor after the thermostat has opened, for whatever reason/
Something to think about.
Hmmmm...mine is always FULL in the filler neck, like..absolutely full...all the way to the spring in the cap. What happens if you fill the thing to the brim?
Hmmmm...mine is always FULL in the filler neck, like..absolutely full...all the way to the spring in the cap. What happens if you fill the thing to the brim?
When I first did the cooling system service, I filled it to the top at the neck and AST a number of times. Burped it twice. Two of my rad hose clamps were worn and leaking so I replaced with full band clamps. Hasn't leaked a drop since.
I suppose it could be "using" coolant but I didn't add coolant for many weeks with no issues. The sensor just started buzzing in the last few weeks.
The other week I either filled the neck first or filled it right after I started the car and it was buzzing. Nothing will get the buzzer to stop other than waiting and driving. I assumed the buzzer had a time limit or something and just stopped on its own.
I will try grounding it again the next time it happens. Got a feeling it could be in the harness. Chassis has 130k. Engine mileage is unknown. Compression checked by IRP and numbers were pretty good.
You can call me a newb if you want. Took the RX out last night. Before starting the car I topped off the water neck. No buzzer on startup. Disconnected my jumper, buzzer came on, reconnected it went off. System seems to be working.
What sort of has me worried is this. After reading this thread:
Sgtblue's description of a coolant seal going bad.
The last couple of weeks the car acted like it was flooded on start up but different. Like it was running on one rotor. (I moved the car 10 feet to wash it once and I could barely get it started. Learned my lesson that time.)
I give it a bit of throttle and it clears up and runs great with no issues. So if my car is consuming some coolant and this rough start continues, I'm worried it won't be long before the cooling system starts getting pressurized, etc.
My car sat in storage for a long time before the guy I bought it from got it back up and running. I feel like I am driving around in a ticking time-bomb.
The only other change I made recently was installing a PFC with a base map. THe cold start issue starts a week or so after this change. The car is definitely running richer overall then it was on the stock ECU. It backfires sometimes on light throttle and downshifts.
06-05-15, 09:35 PM
Took the RX out last night. Before starting the car I topped off the water neck. No buzzer on startup. Disconnected my jumper, buzzer came on, reconnected it went off. System seems to be working.