Did not take the Sienna to Reno, NV last weekend to test the new 2.4" supercharger pulley if the 320hp and 350 torque is for real.. We drove my son's 2000 Odyssey instead. The Sienna got an engine "CHECK) MIL last Friday on the way home from work. My ODB II unit came handy and was able to get the DTC code which is PO330, a bad knock sensor #2 (for the left bank cylinders). I reset the ECM but the MIL came back when the engine reaches 2500 - 5000 rpm. The engine still sound ok though it's operating in fail-safe function in which the corrective retard angle value is set to the maximum.

The knock sensor contains a piezoelectric element which generates a voltage when it becomes deformed, which occurs when the cylinder block vibrates due to knocking. If engine knocking occurs, ignition timing is retarded to suppress it.

Transmission shifting was affected by the MIL, so climbing hills are not easy and had to turn off the overdrive. It drives ok on flat roads though the acceleration is not instant as normal.

Called my local dealer for an estimate and they quoted $1321 (part plus ~ 10.5 hr labor). The labor is outrageous so I just bought the part(s) and did the repair today. It took me 1/3 of the time that they want to charge me. Since I'm already in there, I replaced them both and the harness too (total cost is $338).
My 1998 Sienna with 84500 miles is happy again and will try Lake Tahoe next weekend.

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The knock sensors are located below the water/coolant by-pass rubber hose. The intake assembly had to be removed.

My 1999 Sienna has a check engine light on. This came on 2 weeks ago while I was on vacation so I took it to a local mechanic who told me it was the Code PO330 Bank 2 Knock Sensor and as the car was running fine I could drive it home. So he cleared it and I went on my way. Two weeks later it came on again so I took it to my local dealer, while on the way there it went off. They checked it and it was the Code PO330 Bank 2 Knock Sensor, again. They thought it could be related to the timing and checked the timing belt (it was fine). After $200 of diagnosis they said they would need to remove the intake manifold to access the sensors ($500 more) and then determine if it was a bad sensor or did it point to something else wrong. The car is/was running fine so I decided to not spend the $500 on more diagnosis also I got the impression from the service department that they did not know what was wrong so the solution may be to simply replace the sensor and see if that cleared the problem.
Two days later the check engine light came on again.
Question - Should I spend the $500 to let them diagnose this problem or ignore the light? The salesman at the dealership told me that check engine light (if orange) is for emission problems and therefore running with it on will not harm the engine. But if it turns Red or Blinks I should get it checked. Is the salesman correct? My owner’s manual does not say anything about a Red or Blinking light.