Error code logging vs CEL lights flash and stay on rules ?

[john_o]

Heres my question

What are the rules relating to logging error codes and subsequently a flashing CEL versus a solid lit  CEL?

If I get 1 misfire event , is that flashing CEL?
If I get 3 in total is that a solid CEL?

and if so is total time running and ignition on/off cycle taken into account?

thanks

John

 

[john_o]

FACT 1 : well I can confirm that if the CEL is already solidly lit , it WILL flash when a further error is found, and remain lit afterwards

[john_o]

[old thread but found more info]

CEL Functionality in General:

- Generally speaking, the CEL in VAG cars will illuminate based on two important factors: (1) Priority and (2) Frequency

- The ECU assigns a Priority to each type of trouble code that comes up for some kind of error. The higher the priority, the quicker the ECU lights up the CEL in the instrument cluster

- The ECU will count the number of times that the trouble code has occured. This is known as the "Frequency".

- Based on Priority and Frequency, the ECU decides whether to throw a "soft" code in the ECU memory or illuminate the CEL in the cluster.

- Therefore, not all trouble code occurences will immediately throw a check engine light or cause a limp mode.

[bacillus]

Good to know...