STEP 1. Using scan tool MB991958, diagnose the CAN bus lines.
STEP 2. DTC recheck after resetting CAN bus lines
STEP 3. Brake pedal check
STEP 4. Check the installation condition of the stoplight switch.
STEP 5. Brake booster check
STEP 6. Check whether the DTC is stored again.
STEP 7. Check whether the DTC is stored again.