O2 sensor behavior? Is this normal

Discussion in 'Gen 2 Prius Technical Discussion' started by terramir, Aug 27, 2018.

  1. terramir

    terramir Member

    Aug 3, 2015
    Los Angeles
    2004 Prius
    Ok bought one of those cheap Bluetooth OBD2 dongles. Well doesn't work with anything but torque. Yeah yeah already ordered a obdlink lx now so I should be good in the future. But while playing around I noticed somethings.
    #1 torque seems to only display one O2 sensor bank1x2 and well this is the behavior I observed. Hit the gas dips down then stabilizes itself between 0.7-0.9 but here's the odd thing. When the engine shuts off the reading on the O2 sensor stays at around 0.8 for minutes and then slowly drops down to 0.6 and then sometimes takes a curve that takes 20-30 sec to get 0.1 other times it takes quite a bit longer to get to 0.1 one little step at a time.
    Is this normal behavior with the engine shotdown to stay at .8 and then over minutes and minutes to drop down. BTW just wrote this whole post on my cell and it's been like what 6 minutes or more and it's still up there well I checked again and from min like 8 to minute 11 it slowly dropped from 0.6 down to 0.1 very slowly no curve this time.
    Last time I observed the curve I was parking and it charged the battery for the AC. This time I just had driven like 20 miles this might make a difference. It's just perplexes my it stays up there when the ICE is off and takes a long time to go down.