Dpf egr valve glow plug

[CDR]

I have an Audi q7 2008 3l tdi quattro. Went into safe mode. DPF and glow plug light on. Showed also egr valve airmass sensor and glow plug cylinder 1 as faulty. After forced and drive regeneration all faults have gone and the car is running fine but my mechanic says that I still need to replace the parts.Please advise. Thanks 

[Steve Q]

I'd start off with the sensor first. As replacement of dpf abd egr is costly. However the dpf abd egr could be clogged and may need replacing anyway. 

[CDR]

Thanks for the advice.