My SES light turned on yesterday, took my max to Autozone this morning and had them scan the codes. They said I had a Knock Sensor Code (P0325) and an O2 sensor code (P0153). One of the ppl there said I needed to replace both the Knock Sensor & O2 sensor asap. J/w how many O2 sensors does the '98 Max have and if I replace one, should I replace all of them as well as the Knock Sensor? And should I follow Autozone's advice on replacing both sensors?

 

As far as replacing them "ASAP", I don't think the ks has to be that urgent. I'm sure you know what ks failure means as far as the effects on your cars performance, and such. You will get better gas mileage with a new O2 sensor. Chances are you were driving with a bad ks for a long time, and just found out about it because of your o2 sensor. If you have the cash, replace both. You can get a VERY discounted ks at jerryromenissan.com , and can probably install it yourself. As far as replacing all o2 sensors at this time -- I have no idea. I don't see why it would be necessary...

 

The O2 sensor code you got will specify which O2 sensor is creating the fault. There is a different code for each of the 3 O2 sensors in a 4th gen.

 

P0153 - Upstream O2 slow response (left bank)

The ECU uses the signal from that O2 to determine A/F ratio. If it's gone bad, A/F could be off, causing slight pinging which sets off the KS code. In this case the KS code is considered a ghost code.

Replace the O2 sensor, clear the error codes and check a week later to see if the KS is gone. If so, leave it alone, if it's back, replace it.