Hi guys, I hope you can help me. I have a 2001 RX300, 226K miles on it. It will shift through all the gears, until it reaches running temp, then check engine light comes on and it throws a “knock sensor code.” I replaced both knock sensors and the wire harness and manifold gasket. I replaced all 6 ignition coils and spark plugs. I replaced the shift solenoid. The exhaust is questionable on it (a bit loud right now). Just frustrated and not sure what problem I’m chasing.

 

What kind of knock sensors did you use?
OEM i hope from a reputable source and not those $30 knock sensor kit off of ebay.
So many fakes out there.

P0325 or 330?

 

A knock sensor is used to detect an engine knock, which can be caused by low octane gas. I would try going to a higher octane first to see if the problem goes away. Is the engine noisy when your engine reach operating temperature? If the engine is noisy then perhaps going to a higher weight of oil can help.
"But many transmission-related problems arise from issues that might seem to have nothing to do with the transmission at first glance. For example, not only will a failed knock sensor cause problems with engine performance, but a lot of computer systems disable overdrive after detecting a knock sensor problem."

 

I believe they were Denso brand. I think the code is P0325

 

I’ll try inc octane fuel too. And get back to you. Would a bad catalytic converter cause the shifting issue??

 

You have to go with what the codes tell you. Bad cat will trigger a code too.

There are many threads on knock sensors. The diagnostic only lists 3 conditions

• Open or short in knock sensor circuit
• Knock sensor looseness
• Engine ECU

If only one sensor is reported you can try swapping the wires at the ecu and see if it changes. If the code doesn't change its at the ECU.
The knock sensor hack thread has nice pictures

 

Is the catalytic converter plugged up? Since you're not getting any P0420 codes I wouldn't worry about the cat. You also stated that the car shifts fine until it reaches operating temperature. I would worry about the exhaust system. It might be causing excessive noise that the knock sensor is picking up. Where is the exhaust broken at the front or rear?