W202 from 8/95 on
A/C Diag Codes:
For the fault diagnostics:
1) Ignition on: position 1
2) Temp selector wheel: LO
3) within 20 secs, press the REST and DEFROST buttons simultaneously for more than 6 seconds
4) The LED in the RECIRCULATE button flashes and "dl A" appears on the display
5) Press the AUTO button until all DTC's are displayed and recorded.
6) The current faults are displayed first, then the intermittant faults. "END" is displayed when all codes have been displayed.
7) To erase codes, press v and ^ simultaneously for more than 6 seconds. The display will then show "---". Press AUTO to cancel the erase.
8) Turn Ignition to "OFF" to end the test program.
Hope that helps. Check my page (www house below) for a CD or manual that gives all codes.
Regards . . . . JimF
'94 S500 Cpe
Visit my Mercedes Web Page