P0325 Knock Sensor Malfunction - How serious is this?

I recently bought a 1997 4wd V6. New engine (5vzfe from Japan) was put in 35K miles ago. Overall the truck runs great, but it's had a check engine light since I bought it (P0325). I don't hear very much knocking, if any, but there is a faint tick when running - I hear this sound is pretty common regardless of error codes. When the engine was replaced, so was the camshaft sensor. I was told by the owner that he had this checked out, and the mechanic mentioned something with poor shielding, but nothing was malfunctioning. He just chose to ignore it because he was quoted $1500 to make the light go away. I'm about to take a 7-hour road trip one way this weekend, and I'd like to know how serious this code is and if it can wait to be addressed. Can there be a malfunction code sent without the knock sensor actually be malfunctioning, i.e. everything is still running correctly??

 

It depends. A knock sensor detects unusual "knocking" or "pinging" deep in the engine usually due to bad\early detonation. It often happens worse when the engine is cold and under load.

It generally isn't a big issue if you back off the throttle when you hear "pinging". You can try higher octane gas, make sure all plugs and wires are DENSO or TOYOTA.

The knock sensor will tell the ECU to retard ignition timing if it detects an issue. Which is normal until you get a code. When you get the code though, things are worse than what the ECU can either adjust for or in this case, since this code is for a bad knock sensor circuit, you're looking at a bad sensor, bad wiring or bad ECU. IF you have the sensor replaced, you must use an OEM sensor.

That ticking you hear has nothing to do with the knock\pinging.

 

Okay, so just because I get the code does not mean the ECU is automatically retarding ignition timing? That's my biggest concern, is that I'm driving with retarded ignition when I shouldn't be. I just don't know if the ECU is programmed to retard ignition upon failure of the sensor or not.

 

Dunno. I would guess that it wouldn't do anything when it can't read the sensor.