Does the fault code stay in memory after CIL goes off
 

2001, 1.8 A4
My CIL has been on/off and VAG-COM showed the coolant temp sensor.
Since the car is under 10 years/100 k (Audi extended warranty for this fault).

I have an appointment (Audi dealer) in 2 days and their story is:
- we don't care about other scanners and codes, you bring the car in, we scan it and if the ECT is faulty we replace if free of charge; if it isn't, we charge you for scan (about $120).

Currently, my CIL is off, but it may come back on. The issue is: what if it doesn't illuminate when I take it to the dealer? Will they still be able to see the fault when they scan it?

Thanks,
Nick

Re: Does the fault code stay in memory after CIL goes off
 

Yes they will be able to see the fault, it is usually stored in memory and does not go away until it is cleared

Re: Does the fault code stay in memory after CIL goes off
 

Yes, it was there. ECT changed by Audi (free of charge)

Re: Does the fault code stay in memory after CIL goes off
 

That would depend on the engine management system.
The fault will self clear after the engine management systems sees 50 or more key cycles with the initial fault seen as "clear or non active". That is part of the OBDII criteria. Fault history will however remain active but the MIL will not illuminate
Most drivers will not put up with the MIL activated, therefore a visit to the repair facility with the MIL to be interrogated, usually gets cleared after the repair.

Currently, a data request will now indicate:
When the MIL was set
How the MIL was set
What caused the MIL to set
The primary controller that set the MIL
How long the engine management system was running with the MIL set
How many times the readiness code was run

Three possibilities to the readiness code.
If the fault self clears, the readiness is intact.
If the fault is never cleared, the readiness remains intact.
If the fault is cleared via scan tool, the readiness code resets

As for the Audi dealer. If they were real smart, all 4 wires that connected the ECT would have been replaced with the gold contact versions.