obd port no communication

[ser]

2002 w203 c220cdi showa no stored codes by obd port despite showing faults on dash display came message on 3 different code readers, any ideas?

 

[Trickythemerc]

What messages did the dash show ?

 

[Petrol Pete]

Hello and welcome . What OBD readers were used ? Is it the EML that is lit ?

 

[richard]

You need to use Xentry / Star Diagnosis to read all of the ECU. Cheapo OBDII read wont know most of the control units.

 

[ser]

What messages did the dash show ?

epc and charging fault

 

[ser]

Hello and welcome . What OBD readers were used ? Is it the EML that is lit ?

a very basic reader and toad software

 

[Supernoodle]

Eobd is only for emission relevant faults. So probably only engine and transmission would ever respond.
It wasn't a requirement in 2002, MB were just early adopters.
Even when it was implemented in 2004 very few faults were standardised. ISO15031 was released in 2005 that standardised a list of fault codes. This standard has grown over the years to cover more codes and is the basis for those cheap OBD readers.
So even when you do get a fault on engine/transmission, plugging it into a 20 year old car isn't going to give you reliable results. It may give you a code (the protocols haven't changed), the description will likely be wrong though.