2003 Corolla.
130k miles.
Serviced Regularly.
CEL came on a few weeks ago (P0420) which prevented car from passing smog (California).
Turned CEL off and drove 100mi before heading back to get smogged.
Drove an additional 100mi with at least 6 warmup/cooldown (after smog) before CEL came back on again with same code.
"Freeze Frame" data from CEL doesn't show either O2 sensor values at time of CEL so I decided to drive to work today (30mi) with scanner plugged in the whole way to monitor the O2 sensors along the way. 02s1 fluctuated rapidly within its limits while 02s2 fluctuated little within its limits also.
I was hoping to see one of the O2 sensors reporting out of its limits to pinpoint a fix but now I'm lost at what I should do next.
Could one of my sensors (most likely O2s2) intermittently be becoming "lazy" and be the suspect of the CEL?
If the converters were bad, wouldn't they immediately throw a CEL after warm up? No way for them to be intermittent right? Either their good or bad right?
What should I check next or plan on replacing first?
130k miles.
Serviced Regularly.
CEL came on a few weeks ago (P0420) which prevented car from passing smog (California).
Turned CEL off and drove 100mi before heading back to get smogged.
Drove an additional 100mi with at least 6 warmup/cooldown (after smog) before CEL came back on again with same code.
"Freeze Frame" data from CEL doesn't show either O2 sensor values at time of CEL so I decided to drive to work today (30mi) with scanner plugged in the whole way to monitor the O2 sensors along the way. 02s1 fluctuated rapidly within its limits while 02s2 fluctuated little within its limits also.
I was hoping to see one of the O2 sensors reporting out of its limits to pinpoint a fix but now I'm lost at what I should do next.
Could one of my sensors (most likely O2s2) intermittently be becoming "lazy" and be the suspect of the CEL?
If the converters were bad, wouldn't they immediately throw a CEL after warm up? No way for them to be intermittent right? Either their good or bad right?
What should I check next or plan on replacing first?
