tech2

the only fault with the old sensor was the sensor heater circuit. this will only effect the time it takes the sensor to go into closed loop operation. while its in open loop the vehicle is ignoring 02 data and running on programmed data.

even with bad heater circuits, the exhaust temp will eventually get hot enough for the sensor to work normally. point being, the sensor can still work properly even though a fault is present...so you may not see any difference.

Typerod

ahh...understood. I think its too bad that they need to trigger an CEL for the heater circuit going bad, all in the name of emissions savings i guess, lol.

73shark

But if but if the heater failed and did not set a code and you failed a state emission test, that wouldn't be good either.

Typerod

Yeah thats true. I thought Tech2 said the heater can fail but the O2 sensor can still work as normal once the exhaust got hot enough, and made the O2 sensor go into closed loop operation.

I wonder if it would be detected at all, here in Northern VA, testing is done through OBD2 ports, I guess they can see different metrics they monitor? If it was an actual tailpipe sniff test it may be a different story?

tech2

its sets a dtc so the heater monitor fails. all the i/m monitors must run and pass for the non gas analyzer emission test.

just gas testing alone, ignoring the cel. closed loop = no difference, in open loop, the emission hydro carbons reading should be higher before the cat. would the cat clean it up and pass it anyway...probably.

Typerod

Just an update, all is well, the CEL has not returned.

falconbrother

Thanks for the update. Always like to know how things worked out.

Typerod

No problem! I'm the same way.