Quote:
Originally Posted by sly
Should it also trigger the engine warning light in the instrument cluster? I've been chasing an AU phantom for ages, have noticed that idle smells rich ATM. Just disconnected the HEGO (O2) sensor altogether and the car starts and runs exactly as per usual. The $15K Korean s**tbox I used for a work car 10 years ago had the "stop engine" light come on when the "servicing" dealer left its HEGO sensor disconnected.
Would someone mind disconnecting their O2 sensor long enough to run their car up to operating temp and post back what happens?
TIA,
Tony.
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If the o2 sensor totally failed it would cause the eng light to come on, but they don't normally totally fail, they get very slow in their operation, which means, although they may not be operating correctly, they are still sending a signal to the
ECU (although it is the wrong signal for what is actually occuring), the
ECU does not recognise there is a problem so the light stays off.
If the o2 was left unplugged it will cause the light to come on, but maybe not immediatley, as the
ECU does testing of all it's sensors by doing a test cycle called a trip. Different manufacturers have different trips and different sensors have different trips.
Basically a trip is a test cycle the
ECU looks for, ie the car may have to run at operating temp for 5 minutes and in thet time perform x amount off accelration cyles and do a road speed of x amount (purely speclative cycle) for the
ECU to determine whether the sensor is working correctly.