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FSFRS · 03-23-2022, 09:52 AM

Hey guys.

Ever since I’ve got a p0420 (and installed a 10k miles used oem header) I’ve been monitoring my voltage for the O2 sensors. Installing the new oem header fixed the p0420.

Is the precat sensor supposed to read around 2v? Am I supposed to be reading the lambda PIDs? To my understanding the upstream sensor is supposed to oscillate, correct? It’s just staying steady at 2.2ish volts for o2s11(v).

Also, the downstream sensor, o2s12(v) drops to .1 or so when I’m either cruising (decel) and sometimes when I’m at idle. Is this normal? Or indicative if a leak? It’s around .600-800v otherwise.

My long term fuel trim hovers around 2.

Normal operation? Or am I looking at the wrong data?

It’s not throwing any codes right now, and hasn’t since I put in the new oem header.

03-23-2022, 09:52 AM	#1
FSFRS Member Join Date: Mar 2022 Drives: '13 FR-S Firestorm Location: Houston Posts: 40 Thanks: 6 Thanked 89 Times in 29 Posts Mentioned: 1 Post(s) Tagged: 0 Thread(s)	O2 sensor readings Hey guys. Ever since I’ve got a p0420 (and installed a 10k miles used oem header) I’ve been monitoring my voltage for the O2 sensors. Installing the new oem header fixed the p0420. Is the precat sensor supposed to read around 2v? Am I supposed to be reading the lambda PIDs? To my understanding the upstream sensor is supposed to oscillate, correct? It’s just staying steady at 2.2ish volts for o2s11(v). Also, the downstream sensor, o2s12(v) drops to .1 or so when I’m either cruising (decel) and sometimes when I’m at idle. Is this normal? Or indicative if a leak? It’s around .600-800v otherwise. My long term fuel trim hovers around 2. Normal operation? Or am I looking at the wrong data? It’s not throwing any codes right now, and hasn’t since I put in the new oem header.