Helius

Hi,

2005 ES330 with 203K miles.

Recently, my check engine light came on along with Trac Off and VSC. Using the OBDII scanner, I got the error code P0328 - Knock/Combustion Vibration Sensor 1 Circuit High Bank 1 or Single Sensor.

I am still able to drive the car, I just noticed that the RPM is unusually higher than it normally is. It normally runs ~2000-2500 RPM at 60 MPH, however, it currently runs at ~3000-3100 RPM at 60 MPH. Is it not changing gears?

Anyone have any insights into this problem or if the higher RPM is a cause for concern?

Arsenii

Hello,

What fuel do you use?
Was anything done to the car prior to the code appearing?

The reason why RPM is higher than usual is because any Knock Sensor related code triggers a Fail-Safe mode, which in this particular case, sets the Ignition Advance Angle to 0, as well as disabling the O/D gear.

To diagnose this code, you will need a scan tool capable of reading Engine Live Data, check if your car has Knock Sensor readouts, if not, you will probably need a simple oscilloscope like the one below. Unfortunately, I don't have the wiring diagram for a 2005 ES330, so you will likely need to get a 2 day subscription here to get a manual for your car and find what pins you need to check, unless someone else would chime in.

Reset the code by disconnecting the battery for a few minutes, then start up the car with the scan tool or oscilloscope connected and see how the sensor would behave, if the voltage will stay at 5V right off the bat and won't change a bit, even if you rev the engine a few times, there is a good chance you have a break in the connection between the respective Knock Sensor and the ECU, or the knock sensor itself is bad. Those sensors are connected with the separate piece of wiring under the hood, and it is known to go bad from all the heat there is in the middle of an engine, that is why this specific piece is separate and can be replaced.

If, however, the knock sensor would behave properly, and would show high readings only in certain scenarios, or there is an unusual ticking or hissing sound coming from the engine, there may be a mechanical issue involved, and that is where you will probably need an expert advise from a local mechanic. I would strongly suggest not to drive the car until this issue is resolved, since it may very well ruin an engine.

Hope this helps and best of luck!

Helius

I use Octane of 87 for my car.
There has not been anything done to my car recently. Had an oil change a month ago and drove ~1000+ miles since.

Your explanation of the high RPM makes sense. Thanks for that.

Last night, I just took a peak under the hood and found that the coolant/antifreeze reservoir was basically empty. I freaked out a bit and checked under the radiator cap and thankfully it was still topped up. I don't think low coolant in the reservoir would cause this issue, but seeing that the radiator was still full, I am more certain that is not likely the cause, unless someone tells me otherwise.

I, then, turned on the car to try and listen to any knocking or something but found nothing. The CEL, VSC, and TRAC OFF lights were still on. I took it for a short drive, came back and tried to hear any noise from the engine again, but nothing; no visible shaking either.

This morning something strange happened. I needed to get to work and so I drove the car, but the CEL, VSC, and TRAC OFF were all off. Car shifted gears at high speeds just fine, likely due to the knock sensor being off and so no restrictions, and the RPM was normal around 2k at 60-70 MPH. I am very confused because all I did was open and close the radiator cap (but still had the warning lights ON last night).

I am starting to think its a bad sensor potentially. I'll keep driving it for now and see if I experience any issues again and will update you if I do.

Open to any other suggestions anyone has.

Arsenii

While it is acceptable for that car, I would suggest going for a higher grade if you plan to keep the car for a while.

While it won't be the root cause for those codes to appear, it may be one of its consequences. Try topping up the reservoir and see how long, if at all, will take for it to drain back. If it will empty itself out quickly and there are no external leaks, there may be an issue either with the radiator cap or with the head gasket, it will require further diagnostics.

Below is what knocking or detonation sounds like, if you hear that, stop driving the car immediately until the issue is resolved.


To me that sounds like an issue with the wiring, try starting the car up and wiggling the harness under the hood that goes to the knock sensors, see if that will trigger the codes after they were reset, if that will trigger the codes a few times in a row, then you found your issue.

Hope this helps and best of luck!

Helius

I put in some more coolant and it has been not been drain into the system, its been about a week.

Thank you for the reference video, it was very helpful. Fortunately, I do not hear that kind of sound from my car.

I have still not gotten any of the CEL, VSC, TRAC OFF lights again. As for the harness, I will leave it the way it is for now because I do not want to deal with the hassle of replacing it when the error is gone...for now.

Thank you so much for your reply. Much appreciated.