STEP 1. Using scan tool MB991958, diagnose the CAN bus lines.
STEP 2. Using scan tool MB991958, DTC
STEP 3. Using scan tool MB991958, actuator test
STEP 4. ETACS-ECU coding data check
STEP 5. Using scan tool MB991958, other system DTC
STEP 6. Using scan tool MB991958, other system DTC
STEP 7. Retest the system.
STEP 8. Retest the system.