I got a P0420 code, but before replacing the cat, wanted to check further, so I got an ELM 327 WiFi OBDII reader and am using Dash Command software. I am getting O2 sensor readings that don't make sense to me and am hoping to get some guidance.
Both O2 sensors are new OEM sensors (less than 1000 miles on them) and I have a single spacer on the rear. I have not gotten O2 sensor codes with the new sensors (I was getting codes for the old rear sensor and decided to replace both due to mileage - 145K)
The front sensor readings are fairly steady hovering around 1.5 v. ranging slowly from about 1 to 1.8 v, but did not vary rapidly. I had expected rapid variation in the 0.2-1 v range. Does this indicate a bad O2 sensor? Is there a way to test it? Or does this possibly indicate some other problem?
The rear sensor readings varied from nearly zero to about 0.8 v. By themselves, I would take these readings as indicating I needed a new cat, but since the front O2 voltage did not seem to be behaving as expected, I am not certain.
My lambda readings stayed close to 1. My absolute intake pressure at idle was about 28 KPa.
I was also looking at short term fuel trim, but it never varied from 0.0%, so am not sure it was reading correctly, or maybe these readings show some other problem.
Sorry about no graphs, but I have not figure out how to do graphics for this data yet.
Both O2 sensors are new OEM sensors (less than 1000 miles on them) and I have a single spacer on the rear. I have not gotten O2 sensor codes with the new sensors (I was getting codes for the old rear sensor and decided to replace both due to mileage - 145K)
The front sensor readings are fairly steady hovering around 1.5 v. ranging slowly from about 1 to 1.8 v, but did not vary rapidly. I had expected rapid variation in the 0.2-1 v range. Does this indicate a bad O2 sensor? Is there a way to test it? Or does this possibly indicate some other problem?
The rear sensor readings varied from nearly zero to about 0.8 v. By themselves, I would take these readings as indicating I needed a new cat, but since the front O2 voltage did not seem to be behaving as expected, I am not certain.
My lambda readings stayed close to 1. My absolute intake pressure at idle was about 28 KPa.
I was also looking at short term fuel trim, but it never varied from 0.0%, so am not sure it was reading correctly, or maybe these readings show some other problem.
Sorry about no graphs, but I have not figure out how to do graphics for this data yet.
