I am having the buzzer in the cab go off intermittently while driving. It seems to be throttle dependent (goes quiet on hard acceleration and during in-gear deceleration, buzzer stutters at neutral acceleration). When I last replaced the radiator, the installer grounded the coolant level sensor to the chassis and I have already checked that and reconnected fresh copper to ground. I have been told (by my mechanic) that the buzzer only responds to the coolant system, not the oil level/pressure, but I suspect this is incorrect information. On the other hand, I do have a coolant leak at the water pump (which I am replacing tonight), so if there is one more sensor for coolant that I am unaware of, it would be helpful to know where it is so I can check it. If this turns out not to be the problem, then my rotary mech is wrong, and I maybe have an oil issue that I don't know how to diagnose? My oil pressure gauge is defective (it's been stuck on max since I bought the car), but I've given it an oil change within the last 3 weeks, and it is still topped off with no evidence of leaking and no noticeable power loss, additional vibration, or overheating. This is my daily driver, so this buzzer is ramping up the stress level on my commutes. I really don't want to de-solder the buzzer, but I'm getting close to doing it anyway. Please help.

 

If you have a leak anywhere then the system is losing coolant and inhaling air at that point. If the air bubble settles on the sensor, it will buzz loudly. I suggest taking care of the water pump first then bleeding the system really well, and it should go away. If it persists, then we can try more advanced diagnosis.

The oil pressure sensor being stuck at max can be caused by the yellow/red wire in that part of the harness (at least, it is yellow/red on my S4) being grounded. It is possible that someone removed the condensor that is bolted to the firewall and somewhere along the way the wire got grounded, I suggest taking a look in that area for any non-standard wiring.

 

In my case, though, the sensor that measures the water level doesn't exist if you are referring to the one that threads into the top of the radiator. That wire has already been grounded to the chassis, defeating it's buzzer response. Is there a similar sensor on the motor side?

 

And ignore this repetition, I'm just testing to see how the quote feature works.

 

Forgive me, I must have misread your first post. Yes, that sensor is the one that controls the buzzer. Is there a reason that the sensor was grounded? Having it functional would be safer.

As for why your buzzer is still going off, someone else will have to chime in.

 

Honestly, I think the mechanic broke the sensor after I cracked the stock one and he was installing the koyorad that I have in there now. I didn't even realize that was the case until I started investigating this issue. I will have to buy a new sensor to get one installed, but the leaking water pump comes first. This car is a bit of a Frankenstein from the previous owners, so I might even be dealing with an electrical issue from homemade wiring nonsense and removed parts as you suggested earlier. The hunt continues. Thank you.

 

The water pump has now been changed. I've been checking the coolant level and looking for signs of leaking every time I drive the car, and they look good to go. As expected, the aforementioned buzzer situation has not changed. Does anyone have any suggestions for what other systems I should start checking? To start, I think I'm going to replace the gauge cluster, just because I already have an extra one in my pile of spare parts and I really dislike the aftermarket one the previous owners installed. Maybe the buzzer itself is bad. I'm open to any other recommendations. I don't want to find out too late that I was having some sort of oil problem or something else similarly catastrophic.

 

the buzzer will activate for low coolant and low OIL.

 

That's what I thought at first, too, so I gave an oil change about 3 weeks ago, and it is still topped off. I've checked it every other day or so for the last several weeks just to be sure. Is it possible that a malfunctioning oil pump or OMP could cause this issue? And if so, what is the best way to diagnose each?

 

how is the harness sensor wire grounded?..
Can you snap a couple pics?

and again the buzzer has nothing to do with oil Pressure..just level of oil..(and coolant!..heh,heh!)

 

Burp the coolant system. bet you have an air pocket on the top of the radiator

 

One way to get rid of this is grounding the coolant level sensor wire on the chassis that is if there is no leaks and everything is fine the sensor itself could be bad
and if you check the haynes manual the buzzer is linked to the oil level sensor on the oil pan im pretty sure if you ground that it will go away as well.
Oil pressure gauge u have to replace the oil pressure sender that might be the problem but to check if the gauge itself is working u have to ground that yellow/red wire and check if the gauge inside moves, if it moves the sender is bad if it doesnt move the gauge itself is bad.

 

You have to realize that Grounding the wires to the sensors is not a good idea.
They are there for a reason,to make sure that you have advance warning of a coolant or oil level problem,which the car really relies on.

 

I see no problem with grounding the oil level sensor for testing purposes, i personally have both level sensors bypassed on all 3 cars, but i'm a stickler for checking all the fluids weekly. But as styx said, its best to keep the safeties if possible

 

I definitely intend on keeping the oil sensor active unless it turns out that it is bad. In which case, I will ground it temporarily until I get the new sensor installed. Same with the coolant sensor, which is already grounded. I'm having a hard time finding the oil sensor. Is it located just under the oil filter?

 

Yellow/orange wire

 

The oil level sensor is located in the oil pan, on the passenger side. The item pictured is the oil pressure sensor

 

 

Cool. I'll just have to check my Haynes book when I get home. Thank you.

 

Well if youre going to ground them, at least do 1 at a time, so you can figure out whether its your coolant or oil.

Start with the coolant wire. Its the easiest to get to, and the likely culprit.

 

Coolant is already grounded. Has been since the radiator swap (not my doing). Looks like I need to find oil sensor (I've already been counseled on where to find it), check that it is still in good shape, then move on from there.

 

So the problem has been solved, but it's a bit of a face-palm moment. Finally got my jack stands back so I could look under the car for the oil level sensor. Turns out the sensor was just unplugged! Unbelievable! No more local mechanics for me. It's high time I do all my own work and get all my advice from the forum. Thanks to everyone for assisting this ignorant noob.