I was resetting the lambda today on my 92 190E2.6 after a good cleaning of the sensor plate and throttle body. As I usually do once a year, I check and clear the codes int the engine computer. Every time over the last several years, I have always noticed error codes for the EGR and Air Pump. The MB dignostic manual only states that the codes are (11 & 16) are EGR and Air pump. I know that both are functioning when I check them but was wondering what the computer is looking at to determine these errors. As far as I can tell, the only electrical thing I can see are the vaccume solenoids and Air pump clutch. I have changed the OVP relay within the last year due to the ABS light comming on. Any ideas are welcome.

Thanks
Rod