STEP 1. Using scan tool MB991958, check data list.
STEP 2. Check open and short circuit in SENB, MODP and SENG line between mode selection damper control motor and potentiometer connector (potentiometer side) and auto A/C controller assembly (A/C-ECU) connector.
STEP 3. Check the mode selection damper control motor and potentiometer.
STEP 4. Check whether the diagnostic trouble code is stored again.