Quote:
Originally Posted by blue62
Just for general information:
An important fact to remember when dealing with OBDII and it's related codes.
OBDII is not about engine performance!!!
It's primary function is Catalytic Converter performance.
It doesn't care about engine performance until that engine performance degrades to the point that it becomes harmful to the Catalytic Converter.
With that in mind:
Events such as misfires will set a code and the CEL on the first event.
Why??? Because misfires are immediately harmful to the Catalytic Converter.
An event that would cause a code for say a bad MAF sensor or a slow signal from an O2sensor needs two back events under specific conditions to set The CEL.
On the first event the corresponding code will be logged in the Pending codes memory.
If the event occurs on the next drive cycle, startup, as a back to back event.
The code is moved from pending to permanent and the CEL is lit.
If the event does not occur twice back to back then the codes is removed from the pending codes memory.
So Freserf:
If your reading this, if you unplug the Variocam solenoid and you do not get a code perhaps the DME/ECU does not see it as immediately harmful to the Cat.
So look in the pending codes on your scanner.
Hope this info helps in some way.
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Never thought of it that way ... protect cats ... one of the last cars I rebuilt required a new cat because it was melted and rattling around ... never gave a code though ...