Aftermaket exhaust, PO420 code? - Toyota Yaris Forums

AlaxyGalaxy · 06-15-2016, 06:54 PM

Alright, so I borrowed a bluetooth OBD-II dongle from a coworker and managed to watch the two O2 sensors in real time.

Since I use a free version of an app, I can't log what I graph, but here is the gist of it:

B1S1 varies from 0 to 0.9 (volts, I'm assuming) continuously, and is affected by throttle input.

-When the cat is up to temperature, at idle and very little throttle, B1S2 is stable at around 0.8; that seems a little high to me.
-On compression or during a shift, B1S2 drops to zero, mimicking B1S1.
-At middle throttle, B1S2 mimicks B1S1 almost exactly
-I have not tried WOT.

Sometimes, with very little throttle, B1S2 will jerk up or down, then get back to being stable.

This behaviour seems quite odd to me: I was assuming that at temperature, B1S2 was supposed to stay stable at around 0.5-0.6V and not vary much at all. Mine is stable (albeit a tad higher), but only at low throttle input.

I have to admit I have absolutely no reference point. I think I'll plug the dongle in the Sienna and monitor one bank of sensors, just to see what a system that doesn't throw a CEL is supposed to look like.

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06-15-2016, 06:54 PM	#11
AlaxyGalaxy Drives: 2004 Echo HB 5-door Join Date: May 2014 Location: GMA Posts: 11	Alright, so I borrowed a bluetooth OBD-II dongle from a coworker and managed to watch the two O2 sensors in real time. Since I use a free version of an app, I can't log what I graph, but here is the gist of it: B1S1 varies from 0 to 0.9 (volts, I'm assuming) continuously, and is affected by throttle input. -When the cat is up to temperature, at idle and very little throttle, B1S2 is stable at around 0.8; that seems a little high to me. -On compression or during a shift, B1S2 drops to zero, mimicking B1S1. -At middle throttle, B1S2 mimicks B1S1 almost exactly -I have not tried WOT. Sometimes, with very little throttle, B1S2 will jerk up or down, then get back to being stable. This behaviour seems quite odd to me: I was assuming that at temperature, B1S2 was supposed to stay stable at around 0.5-0.6V and not vary much at all. Mine is stable (albeit a tad higher), but only at low throttle input. I have to admit I have absolutely no reference point. I think I'll plug the dongle in the Sienna and monitor one bank of sensors, just to see what a system that doesn't throw a CEL is supposed to look like.