ENGINE LIGHT, NO CODES!!

[TJT1980]

Hello,
New to all this so apologies in advance if this problem has been talked about before.
I have a 2006 w203 c180k and the engine light came on and the revs started to “pulse” when stationary in drive so took it to a local garage.
Engine codes came up with MAF & breather pipe. On inspection, breather looked new so just changed MAF.
Engine light was still on so checked and found the Lambda sensor was at fault and changed it.
Engine light was still on so they changed the breather pipe BUT the engine light is still on and this time with no codes on the machine.
Mechanics have checked over the electrics and fuel system and can’t find any faults and they don’t know what they can do and apparently the revving is still happening but not as bad.
I am stuck as the MOT is due and booked it into a merc specialist. Has anyone had the same problem or some advice what it is??
properly frustrating!!!!

 

[mioba]

Was the garage that looked at your car a merc specialist.

Did they delete the codes.

Did they use star/xentry.

 

[TJT1980]

No it was

Was the garage that looked at your car a merc specialist.

Did they delete the codes.

Did they use star/xentry.

No it isn’t a Merc specialist - booked in at specialist place next week

they have deleted the codes

not sure if they used Star/xentry

just looking for any other potential problems?

 

[mioba]

Leave it be with the specialist.
Modern cars are complicated and the specialist may know immediately what it is based on his experience/ ability to use and interpret a code reader.
It’s easy to fall into a trap and replacing perfectly good parts based on ones old skool mechanical knowledge.

 

[alexanderfoti]

Yes, as above, use a xentry diagnostic machine will probably give some more information.