Mercedes-Benz S420 Repair and Maintenance
A guide to problems, costs, maintenance and repair for your Mercedes-Benz S420
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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.
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.
The engine wiring can degrade because the insulating material falls off leaving the bare wire exposed. This can cause many problems depending on which wires are exposed and what they touch.
Mercedes-Benz S420 QuestionsWhen I press the gas down my AC decreases. What could it be? (1 answer)
When I apply the gas it decreases everytime.
After sitting overnight it starts right up.