My mother has an '05 E320 CDI with about 37k on the clock. Today she was complaining about low power and she said the check engine light came on. No other symptoms are visible/hearable etc. Is there a way to check for codes on these cars? Any suggestions?

 

I assume you would want to read the fault codes from the car without any tools? This should not work, you would need either Star Diagnosis or a good OBDII reader.

Perhaps it is something like this:
https://mbworld.org/forums/e-class-w211/176313-egr-valve-05-cdi-power-loss.html

 

Whatever's wrong, the car is still under warranty and your dealer will fix it.

 

A good point, I always forget this as our warranty period is only 2 years (some EU countries have more but 2 is the minimum allowed by EU).

 

Assuming it was not a 2004 delivery "optioned" car...

 

Classic description of failure of the EGR valve. I bet when she restarts the car, it drives fine for a while and then loses all power. The dealer will replace it with a newer version that shouldn't have this problem. Lots of discussion about this in past threads.

 

Thanks. I will look more into this.

 

As stated above