If a DTC was recognized

1. Repair malfunction
2. Check DTC memory (function 02)
3. Erase DTC memory (function 05)
4. Check coding (function 01) or code control module (function 07), respectively.
5. Perform basic setting (function 04)
6. Check DTC memory (function 02) and erase DTC memory (function 05), if necessary.
7. End Output (function 06).

If no DTC was recognized and complaints have been received regarding A/C system. (e.g. compressor inoperative or intermittent, control of system unsatisfactory, fresh air blower speed cannot be regulated). 

1. Read measuring value block (function 08). See READ MEASURING VALUE BLOCK (FUNCTION 08)  .
2. Perform output Diagnostic Test Mode (DTM), function 03. See OUTPUT DIAGNOSTIC TEST MODE (DTM) (FUNCTION 03)  .
3. Test A/C system cooling performance. See A/C REFRIGERANT SYSTEM, TESTING .

If no malfunction is recognized by A/C control head - E87- and the temperature of the air from outlets in instrument panel (left and right) can not be adjusted or controlled 

• Check valves for coolant pump, electrical tests. See AUTOMATIC CLIMATE CONTROL SYSTEM, ELECTRICAL TESTS  .