I tried changing everything from plugs wires, injectors and so on and still have a check engine light with a code P0304. My cars computer is making a high pitch beeping sound. Kind of like those high pitch dog whistles. Could my computer be bad?
Faulty Computer?
- Thread starter JMac101
- Start date
- Status
For the price of a computer you could have it properly diagnosed by a qualified technician. Computers don't normally whistle. Do you think it might be coming from somewhere else. I know you've changed the #4 coil pack but have you tried switching packs to another cylinder? If you stuck it in, say, #3 and the code that sets is P0303 then you know it's the coil pack.
Last edited:
Could the high pitched sound be from a vacuum leak?
Originally Posted By: duaneb9729
Could the high pitched sound be from a vacuum leak?
Bingo!That may be it. That would cause a misfire too because the vaccuum leak would lean the mixture to the point of misfire. Of course that usually generates a P0300 Random Misfire code, not a specific cylinder like in this case. But still, worth it to chase down.
Could the high pitched sound be from a vacuum leak?
Bingo!That may be it. That would cause a misfire too because the vaccuum leak would lean the mixture to the point of misfire. Of course that usually generates a P0300 Random Misfire code, not a specific cylinder like in this case. But still, worth it to chase down.
You can only hear it with motor off. I changed the plugs, wires, injectors, coil pack. I still have the #4 code. I dont know what to even change next and I dont have the money for a mechanic right now.
Zero in on the noise.
If it IS the computer, it is probably toast.
This is NOT normal.
If it IS the computer, it is probably toast.
This is NOT normal.
PCM/ECM whatever you want to call it is the LAST thing you should replace after all options have been exhausted. In 10 years of working on cars, I've only seen about 10 bad PCM units.
I have the cylinder 4 misfire code. I changed the plugs, wires, injectors, injector harness, fuel rail, egr, throttle position sensor, map sensor all that stuff. Still have the code and now I have the high pitch whistles coming from the computer or in the area of the computer. It whistles for like 40 seconds after the car is off. Thats why I asked about the computer. I dont know what else to do
Did you change the boot that runs from the coil pack to the spark plug when you replaced the coil pack? Also, I would definitely recommend switching coil packs between cylinders 3 and 4 and rechecking the codes after you've driven it for a while when it is misfiring. Just because the coil pack is new doesn't mean it's good.
Not to dump on anyone's cracker, but how can a PCM whistle? It's all solid state circuitry.
Depends on what's inside the PCM. If it had a switching power supply (to convert 12V to 5V and 3.3V for the digital circuitry), it very well could make noise--these switching power supplies have inductors and transformers and they can sometimes make noise depending on the switching frequency used.
Ever heard a TV set whine before? I haven't in a long time, but that doesn't meant that they've stopped (the CRT ones anyhow)--it means that my hearing isn't as good as it was back when I was 8. The whine comes from the flyback transformer.
Ever heard a TV set whine before? I haven't in a long time, but that doesn't meant that they've stopped (the CRT ones anyhow)--it means that my hearing isn't as good as it was back when I was 8. The whine comes from the flyback transformer.
Any high-current driver circuits in the ECU that are powering an abnormal load could also whistle. The coils might be driven by such devices.
The first 486 motherboard I bought decades ago would faintly whistle a different note with a press of each mouse button. Prius's make a whistle when running on battery for the same reason.
The first 486 motherboard I bought decades ago would faintly whistle a different note with a press of each mouse button. Prius's make a whistle when running on battery for the same reason.
Remember, a computer 'whistling' is not normal - something is broken. So normal does not count!
- Status
