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Probably will buy a new one and replace it on my first oil change, just crossed the 300 mile mark on my brand new engine so breaking it in before the warranty from Mazda runs out. anyway, i'll update the thread once I have this buzzer figured out.
Were you able to resolve your buzzer issue?
I'm helping a friend with a coolant buzzer issue on his 93. In his case, the low coolant light is on, as well as the buzzer beeping.
We checked continuity from the coolant level sensor to the grey chassis connector and confirmed there is no break in the wiring. We grounded the wire at the sensor connector and waited 10-15 secs and the buzzer stopped beeping.
This lead us to replacing the coolant level sensor itself with a new Mazda OEM sensor. After topping off the coolant level and making sure it was above the sensor, we started the car and the buzzer came back on.
We then grounded the wire at the sensor connector again and after 10-15 seconds, the buzzer stopped beeping.
So it appears while there is continuity in the stock wiring, perhaps resistance is too high in a section of wire or the pins have light corrosion/not fully seated affecting the quality of the ground.
We plan on checking resistance next. Any feedback is appreciated.
I'm helping a friend with a coolant buzzer issue on his 93. In his case, the low coolant light is on, as well as the buzzer beeping.
We checked continuity from the coolant level sensor to the grey chassis connector and confirmed there is no break in the wiring. We grounded the wire at the sensor connector and waited 10-15 secs and the buzzer stopped beeping.
This lead us to replacing the coolant level sensor itself with a new Mazda OEM sensor. After topping off the coolant level and making sure it was above the sensor, we started the car and the buzzer came back on.
We then grounded the wire at the sensor connector again and after 10-15 seconds, the buzzer stopped beeping.
So it appears while there is continuity in the stock wiring, perhaps resistance is too high in a section of wire or the pins have light corrosion/not fully seated affecting the quality of the ground.
We plan on checking resistance next. Any feedback is appreciated.
Hey, sorry for the late reply. I chased the wire alll the way back to inside the cab, that didn’t lead to a solution unfortunately, and I sold that car shortly after that. It was a mystery that remained unsolved...
resistance would be my next point to look at, you’re on the right track.
Hey, sorry for the late reply. I chased the wire alll the way back to inside the cab, that didn’t lead to a solution unfortunately, and I sold that car shortly after that. It was a mystery that remained unsolved...
resistance would be my next point to look at, you’re on the right track.
Ironically, the buzzer and low coolant light resolved itself this past weekend when my friend started his car again. We did measure resistance from the chassis side connector vs. at the new coolant sensor connector and it was just under 1 ohm, which should be fine.
If the issue appears again, we will dig deeper and report back.
The intermittent issue came back and we then tested continuity from the engine bay to the connector at the gauge cluster. Continuity checked out fine. Low coolant light still on and buzzer still nonstop. We isolated the issue to the cluster.
To test the theory, we then swapped a known good gauge cluster and the light and buzzer went away. Everything worked normally and as expected.
My friend then sent his cluster to Geoff P from Circuit Board Medics and sure enough, there were leaking caps and cold solder joints. Geoff checked the circuit for the buzzer after his repairs and confirmed the issue is resolved.
We are waiting for his cluster to be shipped back and will confirm the fix.
In summary, if the low coolant sensor checks out, and there is continuity in the single wire from this sensor all the way to the connector behind the gauge cluster, then the issue likely exists within the cluster.
If the fix was to repair cold solder joints and leaking capacitors then it sounds like the culprit is the Speedo Circuit Board. I'm interested to see what was repaired and replaced.
If the fix was to repair cold solder joints and leaking capacitors then it sounds like the culprit is the Speedo Circuit Board. I'm interested to see what was repaired and replaced.
Geoff suspected the same regarding the Speedo Circuit Board. We'll take photos upon receiving the cluster back. If there are any specific shots that you'd like, let us know.
I've read through your threads on the gauge cluster and CPU2; lots of great information in there. 😁
Thanks! I'm glad the speedo board and CPU#2 threads helped you understand their function.
I'm curious to see TR1 (Q1) and TR2 (Q2) and their associated components. They are easily seen at the top-center section of the speedo board (without removing the speedo face).
It's good to hear that a repair was successfully made. Enjoy!
Hey
Thanks for the precious informations in this topic.
Yesterday, after replacing the oil pressure sensor, I had the low coolant and buzzer. I really didn't understand because I knew the coolant level sensor is in the front of the engine, not in the oil filter area... But, thankfully to you guys, I quickly found out this brown/white wire coming out the harness near the oil pressure sensor, that was loose after I struggled changing the pressure sensor in this tiny area.
Made a quick fix and voila !!
Attached below are some pics, may be useful for some newbies like me 😉 The wire loosed from its plug The quick fix Voila
Thanks! I'm glad the speedo board and CPU#2 threads helped you understand their function.
I'm curious to see TR1 (Q1) and TR2 (Q2) and their associated components. They are easily seen at the top-center section of the speedo board (without removing the speedo face).
It's good to hear that a repair was successfully made. Enjoy!
We finally had time to install his repaired cluster yesterday and here are some photos (the cluster repair fixed his low coolant light and buzzer issue):
I have the coolant buzzer issue on my car, searched and read just about every single "Coolant Buzzer" thread available in the world. All say ground the wire out to shut up the buzzer, or there is a bad sensor, or bad wire.
I started my troubleshooting and found a few things wrong, Continuity from the "Black" wire that goes from the water pump sensor to the "Brown/White" wire was not real good. So I repaired both ends of the wire with new connectors, tested continuity, perfect.
Moved on to the "Brown/White" wire, found that the wire at the connector was broken. So I got a new connector, spliced the wire, soldered it to the new connector, tested continuity, and resistance (check in at 0 Ohms indicating a good solder).plugged the wire back in, buzzer lives on...
Now I search around and I find my Oil level sensor is also needing repair, I follow basically the same procedure above. repair connectors, solder wire, test to make sure its a good solder, plug it back in, buzzer lives on.
So lets move on to the "add coolant" portion of the troubleshooting, because that's in all of the threads I find. I get my Lisle funnel, start the car, and let the car get rid of all air bubbles in the system. this goes on for about 90 minutes, just to be sure. checked all coolant levels and buzzer lives on....
At this stage of the game it can only be the sensor right? even though its a brand new water pump assembly in the car with a new sensor, I buy a new sensor anyway. put in the new sensor.... and wait for it... buzzer lives on!!!
So I say screw it, i'm grounding this wire and moving on with my build because I just cant stand that damn thing buzzing all day... so I grab the wire, ground it and.... buzzer lives on!! WTF??!? I ground both the oil level sensor and the coolant level sensor and nothing, buzzing continues without any sign of stopping, and yes I waited the required 20 seconds, heck I grounded it and waited 10 minutes with no change.....
Now I bust out my workshop manual, find the wiring diagram and see where this stupid thing goes into so I can verify that its not broken somewhere. From my understanding, it actually goes into the X-18 harness, behind the instrument cluster. so I pull the cluster and everything is plugged in correctly.
Now i'm stuck, no grounding works all the wiring is repaired and checks out fine, but my buzzer doesn't shut up... the only time I got it to shut up was when I had the cluster out and I left the plug that goes into the cluster that feeds the temp gauge out, when I did that no buzzer, but that more than likely is because the circuit was not complete.... Anyone have any ideas? i'm about to go nuts with this buzzer....
What other systems use the same buzzer?
Is that buzzer connected to oil pressure and or oil level sensor? Perhaps another system?
I have a condition where there is no buzzer at idle, and when the engine revs seemingly the buzzer comes on at higher engine loads.
I have isolated the coolant level sensor I think both by grounding it out and as well as putting a 3 ohm resistor in line, with no change. I think the sensor is OK as it is completely disconnected and reacts the same.
Still there is no buzzer when idling, and when a higher rpm is used, seems to activate the buzzer.
Any other systems to check where the buzzer is being activated from?
Pretty certain my oil pressure is good..if not higher than normal...from a pineapple oil mod I did not request. but I can check that if it is a likely cause.
This is just a quick note but take a look at the Body Electrical Manual (BEM) for troubleshooting the Body CPU. It receives multiple inputs to sound off the buzzer.
The link here: F100 CPU Post 7 cites the specific Flowcharts to use.
Let us know what you find! Does that help?
P.S. The problem may be tied to the over-rev alarm since you mentioned it happens during higher rpms. And how high of RPMs are we talking?
Last edited by Gen2n3; 02-11-20 at 08:29 PM.
Reason: Added post script.
Not very high RPM/Load, just pulling away, or if cruising and giving it a bit more throttle very mundane amount of change.
It’s a fairly recent phenomena, and I didn’t think much of it, assumed it was the coolant sensor as I have had that issue before if the system is not topped up to the ml…
Since I do not use the vehicle frequently, I went to spend the time to fix it and explore what I thought was going to be a faulty level sensor…unfortunately it is something else ambiguous to me ATM.
If anyone has any advice what to look into from experience or similar symptoms, would really appreciate some thoughts on it.
Can I add any details that might help narrow down and target what might be activating this buzzer?
I Thankfully don’t have very many gremlins in my car, and this is one I would really like to find and step on.
Also does anyone know about the PNW PFC tuning scene? Portland Oregon to be more specific, Need some help finishing up an incomplete Steve Kan tune.
Last edited by rotarypower101; 02-11-20 at 10:50 PM.
I don't know how significant it is, but is seems to not activate the buzzer below the 2000 RPM range. Can rev and play with throttle (while parked) below 2k with no buzzer, above 2k it activates the buzzer.
My oil pressure gauge is rising with throttle and looks "normal" I have not added an independent gauge to validate yet, nor am I inclined to think that is the issue?
Is it possible it could be a "high over-rev alarm buzzer" that could have some "old hardware" symptom where the activation threshold has been reduced? Similar to those faulty caps that were replaced above?
Is there a way to quickly test for a complete wild guess like that? Might there be a way to disable the "Over-revolution warning alarm"?
Struggling to think of what to contribute the symptoms to, and how to track it down logically.
Last edited by rotarypower101; 02-11-20 at 11:32 PM.
Though, based on what you said, I don't think this **** can 'lose' 6000rpm, unless you manipulated the dash clusters recently.
Also, I may be wrong, but i'd say the high rev buzzer is slightly different than the low coolant or start-up buzzers. I'm really not sure about this, but i'd say it's not the same pitch.
I guess you already verified your coolant level, right? Filled up to the top?
Besides that, I guess there are many sensors that can activate this buzzer, but I've no idea which one here...
unless you manipulated the dash clusters recently.
No manipulation of the cluster.
BY no means am I asserting this is the issue, completely spitballing based on very little feedback from the car and exploring why I am getting a buzzer out of nowhere that is apparently different and strange to my normal observed operation.
I can easily be wrong, but to my ears it sounds like the “exact same” buzzer that the low coolant warning uses, same pitch and sound. But maybe they use two identical buzzers.
When disconnecting the coolant level sensor, we would expect the buzzer to alarm because of lack of ground/the expected 3 ohm?
My coolant alarm system seems to operate as expected if I understand its feedback and functionality.
I get a ~10sec buzzer if grounded.
I get no buzzer if coolant level sensor plugged in while parked and started
I get a constant buzzer if disconnected or open.
When I rev past 2k range, I get a constant buzzer.
Again want to reiterate, I am not confident that is the issue, but searching for something to grasp at to resolve the issue…strange it would be seemingly RPM based and at a sharp cutoff point, but I was thinking the fluid level “could” change on water pump cycling faster, but seems to Not be the issue if the above is true as I removed it from the system and get the same variable RPM feedback?
Even if I "sneak" up on the RPM slowly, the buzzer seems to alarm at a sharp definite repeatable point in the RPM.
Last edited by rotarypower101; 02-12-20 at 12:40 PM.
Does anyone know the electrical system enough to postulate how to temporarily strategically disable Only the RPM warning signal to narrow down the causes of this alarm?
What might I be looking for to explore disabling Only this input leaving other functionality alone?
Does anyone know if the FD specifically has a potentiometer to adjust the high rev point? And might there be a thread or post detailing its adjustment someone knows about from seeing it or reading on the topic?
Last edited by rotarypower101; 02-12-20 at 12:33 PM.
The buzzer is all the same - it's in CPU#2. There's one buzzer for everything - low oil, low coolant, shift up.
Low oil pressure will NOT cause the buzzer to go off.
The link above about changing the RPM point of the buzzer is on an FC, there's no setting that I know of that will do it on an FD.
It sounds to me that the buzzer is thinking you're at 8000 RPM and it's going off. Either the tach is putting out the wrong thing or the CPU#2 is bad/flaky.
I would advise not pulling any wires that would temporarily disable the buzzer.
There is no method of adjusting the over-rev buzzer. It is hard-coded in the speedo board.
Before you take any further measurements, take a look at the Body CPU. Inspect it for leaking caps or other potential damage. Do the same with your speedo board. Take some pics on anything that you believe to be suspect. Post them and I could offer some advice.
Last edited by Gen2n3; 02-12-20 at 08:46 PM.
Reason: Corrected spelling error.
I'd like to add one more item to inspect: the tachometer.
Take a look at the solder joints along each of the 22 pins on IC1. This may not show much because you would be looking at the top side of the IC chip. The bigger tell would be the back side of the small tach board. The only way to access it would be to remove the tach needle and face. Take a look at Rev counter going crazy Post 2 and download the PDF file. It gives step-by-step directions to remove the tach needle and face without breaking anything.
Because the procedure to remove the tach face is more involved, hold off on that for the moment. You may still inspect the exposed side of the tach board for any potential problems. Let's try to eliminate any problems in the Body CPU and Speedo board first.
I'd like to add one more item to inspect: the tachometer.
Take a look at the solder joints along each of the 22 pins on IC1. This may not show much because you would be looking at the top side of the IC chip. The bigger tell would be the back side of the small tach board. The only way to access it would be to remove the tach needle and face. Take a look at Rev counter going crazy Post 2 and download the PDF file. It gives step-by-step directions to remove the tach needle and face without breaking anything.
Because the procedure to remove the tach face is more involved, hold off on that for the moment. You may still inspect the exposed side of the tach board for any potential problems. Let's try to eliminate any problems in the Body CPU and Speedo board first.
How does that plan sound?
I’m having the same issue. I changed the coolant sensor with no change. I will attach a video. This is way quieter than when I started it.
I would guess that you have bad capacitors on the speedometer circuit board (inside the instrument cluster) or similar inside the Body CPU (CPU#2). You can also read more threads that deal with bad capacitors on the speedo board. Do a search with my screen name and the words speedometer and odometer. You may be reading for a while.
Tell us more about your car. Is it stock or list the mods you have installed? Other than replacing the coolant level sensor, what else did you work on under the hood or dash recently? Does your odometer work? Do you have cruise control and if so, does it hunt for a constant speed when set?
I may have to look into this CPU#2 . My odometer recently started disappearing and when it flickers on and off while driving a buzzer goes off and on at the same time. The 2 related?
Given your description then follow the link & advise offered in the above post, Post #48. It really sounds like the root of your problem is leaking capacitors in the Speedo board.
09-07-19, 04:39 PM
