Well, one way to see if the CEL works; is to use VCDS to do a series of "output tests" on the speedo cluster. It will turn on each of the lights in the speedo cluster.
Here is a video; showing this process and which light come on and off (this is also; an excellent way of testing your gauges if they are not working).
https://www.youtube.com/watch?v=5c4SRoVdojU
https://www.youtube.com/watch?v=I3--GvnKE10
Ross-Tech: VAG-COM Tour: Output Tests
If all the lights work; then you are ok, otherwise the light bulb in the speedo cluster would need to be replaced or the cluster needs to be repaired?
To do this procedure in VCDS: you would:
1. select: control module: click on "select"
2. select: #17 instruments
3. selectL #3 output tests
4. then there is a guided series of tests; that activate different aspects of the speedo cluster, including the "CEL"
Here is a video; showing this process and which light come on and off (this is also; an excellent way of testing your gauges if they are not working).
https://www.youtube.com/watch?v=5c4SRoVdojU
https://www.youtube.com/watch?v=I3--GvnKE10
Ross-Tech: VAG-COM Tour: Output Tests
If all the lights work; then you are ok, otherwise the light bulb in the speedo cluster would need to be replaced or the cluster needs to be repaired?
To do this procedure in VCDS: you would:
1. select: control module: click on "select"
2. select: #17 instruments
3. selectL #3 output tests
4. then there is a guided series of tests; that activate different aspects of the speedo cluster, including the "CEL"