I get purge volume control valve and knock sensor DTCs on 1996 Nissan Maxima

nissan
code
valves
maxima
sensors

#1

I get P1445, which is purge volume control valve and P0325, which is the knock sensor, codes.



Do I need to replace the two, or do I have to do more diagnostic work before I can be sure those are problems?



Also, can I clean either of them, or do I need to replace them?



I understand the purge volume control valve controls how much of the evaporated gasoline trapped in the charcoal cannister gets let into the engine. So, it shouldn’t be related to drivability. Is that right?



My car has been hesitating under moderate acceleration with the acclerator pedal 1/2 to 2/3 down. I rarely do full-throttle, so I don’t remember how it was under full throttle. The knock sensor should be related to this problem. Is that right?


#2

Fix the knock issue first. When was your last tuneup? The evap system likely will not cause the knock issue in a well tuned engine. But a bad knock sensor will retard your timing and cause bad performance. The evap may need to be fixed as well but wait on that.


#3

I changed the spark plugs about 50,000 miles ago with platinum plugs. I would think the plugs would be all right. I was thinking the knock sensor could cause the car to hesitate under load, because the timing cannot be advanced as much as it could be.