Mercedes-Benz S420 Repair and Maintenance
A guide to problems, costs, maintenance and repair for your Mercedes-Benz S420
Never overpay. Check prices with our estimator
Verified by mechanics, reported by drivers like you
Ask a mechanic in our community
Mercedes-Benz S420 ProblemsClosing Assist/Door Lock Issues Due to Pneumatic System Problems
Problems with the pneumatic system can cause closing assist and door lock issues.
One or more door windows may stop working due to a failed window regulator. Replacement of the failed regulator will be necessary to correct this concern.
A faulty mass air flow (MAF) sensor can cause erratic/rough engine operation and fuel economy issues. Since this sensor measures the actual amount of air entering the motor, when it fails, the engine control module (ECM) takes the wrong information and delivers incorrect volumes of fuel to the cylinders.
Mercedes-Benz S420 QuestionsThe heat works great but blower continues to run when the car is turned off? (1 answer)
Replaced the resister. Blower continues to run w.hen car is off. Have to unplug resister to shut off. Heat, air conditioning, blower and controls all work great, except for blower not shutting off when car is turned off.
When I apply the gas it decreases everytime.