Nissan Repair: p0141 and p0325 on a 2000 villager 75k, obdii codes, knock sensor

Question
Hello,
I have a 2000 vilalger with two OBDII codes.  P0141 O2 Sensor heater Circuit malfunction and p0325 knock sensor.  The van seems to run fine.

I've searched several forums to see if anyone has a real "fix" for this combination of codes. The closest I've come is a Maxima owner (3.0l engine they had in the 98 and earlier quest/villager) who said that changing the ignition coils did the trick for him. Anyone with a 99 or later 3.3l engine with these codes and what you found to correct them.

I've changed the downstream o2 sensor and the upstream sensor to no avail. I've read someone talking about their mechanic suggesting rotor, distributor cap and plugs and wires while you're at it and I've done this figuring even if it doesn't fix the codes, can't hurt to do a general tune up.  The codes remain.

I am going to change the distributor next as I got a very cheap deal on one recently. The maxima owner I referenced above found that changing all six ignition coils fixed the problem (this is a distributorless engine with a coil for each plug).  The ignition coil in my Villager is integrated into the distributor, so...my thought was give it a shot.

Again, it runs OK, but I guess I'm a bit obsessive with the blasted cel!

I have focused all my attention on the O2 sensor because eveything I read seems to indicate the Knock Sensor likes to go off in conjuction with other codes and is seldom the problem itself.  If you've repaired oen of these Please help!

John  

Answer
John,

Change the coils since they were defective on the 2000 model.  Reset the codes and see if they stay off.  My bet is the knock sensor will come back but the heater malfunction will stay off.  You will love the difference in how the van performs with the new coils.  I have a 2000 Maxima with the same engine and the coils did the trick for me.