Quote:
Originally Posted by piper6909
I think SAI test happens at idle. Did you let it idle for at least 2-1/2 minutes?
It only does the EVAP test if your fuel tank is between 1/4 and 3/4 full, so check your fuel level.
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My current understanding of the SAI test is that it happens in closed loop. When the ECU decides it is ready to test the SAI it turns on the air pump while in closed loop. the ECU then looks for a voltage drop to .200 millivolts at the pre cat o2 sensor within 2 seconds. This voltage drop is conformation to the ECU of the correct excess o2 in the exhaust in the correct time frame Thus the SAI is working properly.
If the ECU fails to see those changes it throws a SAI related code.
The SAI function in open loop at start up is to help the cats warm up faster and help burn off hydrocarbons.
This is my current understanding of how the SAI works and how the ECU tests it.
I have not researched the EVAP system yet so my understanding of it is damn little.
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