At this time, I recommend to remove the EGR valve and clean it with a soapy water solution, clean the valve itself thoroughly, rotate the valve and clean the ports then reinstall it and clear codes and retest. If it returns you will need to diagnose the wiring before condemning the EGR valve.
Here is the procedure for testing, you should be able to test the wiring with this flowchart and the connector pin charts. If you want to do this yourself, let me know and I'll post the connector pin charts for the ECM and EGR valve...
Here is the Diagnostic Procedure --->> Click Here to view <<---
This is the Manufacturer Specific Code Diagnostic procedure that most closely matches the "Generic" code you posted as being retrieved from your vehicle. If you want to be sure about the code and correct diagnostic procedure, I HIGHLY recommend to scan with a FACTORY scanner (DRBIII) or the Mercedes scan tool.
I recommend scanning at the dealer as many of the "Generic" Scanners or Code Readers have problems communicating with Sprinters and due to that, either are unable to retreive codes, or the "generic" codes that are retreived can sometimes be incorrect....
Keep me posted and let me know if you have any additional questions...
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