Took a quick cruise this evening and when i got home i popped the hood to check some new hoses that i had installed. In doing this i found the o2 sensor wasnt even plugged in??? i plugged it in and checked for codes but nothing popped up. didnt seem off during the drive (no cel) tho i did notice there was a bit more fuel smell coming from exhaust and a small loping at start up. could that sensor being unplugged have anything to do with either of those start up issues? i have beeen reading posts on o2 sensors for almost 2 hours now but didnt come across anything about having one unplugged. thanks guys
Diconnected o2 sensor?
- Thread starter spooln6cyl
- Start date
O2 codes don't just happen. Several parameters must be met. Not to mention they're two trip logic. Depending on model year you may not get a heater code. Lastly, in a steady state condition the system defaults to slightly rich with a floating lambda input. About .9 iirc
Welcome. It's an indication of how close the TCCS can get the mixture in open loop using the learned value. That's not an accident as Federal emissions standards are involved. The other thing to remember is O2 sensors have the least authority of any in the engine for what should be obvious reasons and they exist for only one: to service the catalyst. Simply put they're emissions devices.
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jetjock;1875758 said:
To expound...
I don't remember the number off the top of my head. But one of Toyota's books is more or less on how to use the scan tool. It is a class to be taken after all the others are done. In it, they mention strategy and priority. In case you couldn't figure it out from the base lessons. It straight up lists oxygens sensor signal as last to look at for driving difficulties.
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Keep in mind also that our O2 sensors are a very old design, and since we dont have OBD2, theyre comparatively crude and rudimentary. As mentioned, they have little influence on how the car runs on the whole, but having a good one should boost your mpgs a bit and not have it run quite so rich.
Orion ZyGarian;1875889 said:
Well, not quite. It isn't designed to control the engine. The switching of voltage is intentional. It keeps the cat in its 450mv operating range.
hey thanks for the responses to this. after doing some searching i couldnt really come away with an understanding of "two trip logic". maybe i overlooked something simple. i drive an 88 turbo and i picked up a lot of good info on the heater code , so thanks again jetjock for that mention.
Simply put it means the fault must exist for two key cycles before the MIL is illuminated. All the parameters required for the code in question must also be met. That can be fairly involved for some of them. Speed, rpm, temp, time, etc.