I've been driving the Z for a bit now and the ses light popped so I checked it the code was a p0306. I hooked up my laptop and did a live data diagnosis and found that I had a bad ignition coil. Replaced the part and cleared the code but a couple days later the light came back on this time the code was a p0430. I tried searching for it and found people with test pipes or HFC's have this problem. I know it's not a vacuum leak but how do I tell if it's my o2 sensor or if it's my actual cat? My mileage did drop a little bit and my exhaust fumes out a thin white smoke I know it's normal on startup but it continues even after my car is warm. That's all I have figured out so far. If you guys could give me some insight that would be great and thanks in advance.

 

P0430 is almost always a problem with the CAT. Here’s a good explanation of the code and its causes:


How many miles on your Z?

 

It's an 04 with 95k miles on it. I'm thinking it probably is the cat because of the p0306 but I could be wrong and cats aren't cheap. So I need to be sure

 

Old thread but similiar issue...

Anyone know exact voltages (obd2 PID) how front AF sensors and rear o2 sensors are scaled by 350z ecu when read from obd2 port? Meaning, what sensor1 and sensor2 obd2 voltage (= PID value) is at stoich (14,7afr).... b1s1, b1s2, b2s1 and b2s2?

Service manual wont help since there are not scaled values in manual. Would help a lot to diagnose my broblem (car is 2004.5 so widebands on front sensors)