2002 Toyota Sequoia P0325 Knock Sensor Malfunction Bnk 1 or Single Sensor

Thanks everyone for the input. Yes the P0325 is a trouble code that the Auto Zone Tech got when he connected my car to the computer. Today the plot thickened. The A/C is now making alot of noise. It sounds like a industrial fan when turned on high. The air out-put seems to be the same. Could these be related or am I just experiencing problem #2. It seems things do like to come in 3’s. I called about getting the sensor checked and the estimate was @ $1500.00. The Tech said they would have to take apart the motor to get to the sensor. If I don’t get this fixed could it damage my motor. I don’t really have that to spend on a motor right now. But I would hate to have to buy a new motor. Thanks everyone for taking time to reply, I greatly appreciate it. Have a great week.