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2003 Mercedes-Benz S500 Problems

RepairPal has identified the most common problems with the 2003 Mercedes-Benz S500 based on complaints from actual vehicle owners. We'll tell you what the problem is and what it'll take to fix it.

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22
Known Problems

The relay which turns the airmatic suspension pump on may fail causing the pump to run continuously. This can result in failure of the pump motor or a dead battery as the pump motor will continue to run after the car is turned off. Also, Worn airmatic pump mount bushings can causes noises in the front axle while driving on bumpy roads or a buzzing noise while the pump is running.

CD changers, command units, voice control units, PSE units, and Tele Aid units are prone to failure, especially in early models.

Front thrust arm and control arm bushings can crack and sometimes tear completely. If this is not repaired quickly, damage to the front subframe unit will occur, which is very expensive to repair. Updated control arms (that prevent damage to the subframe when the bushings wear out) are available.

Problems with the pneumatic system can cause closing assist and door lock issues.

The active body control system can leak fluid from numerous areas, including the tandem pump, hydraulic lines, struts, and/or seals. If it is not repaired, the vehicle ride height could drop too low and cause damage to the undercarriage.

Cup holders break easily, especially if sticky liquids are spilled into the cup holder mechanism.

The crankshaft position sensor may fail. Symptoms of this are: The engine will crank—but not start—especially when the engine is warm. The car may start again if it is left to cool off, but it may run roughly or have poor performance.

The rubber bond in the harmonic balancer can decay, which causes the balancer to move and work its way toward the timing cover. If the balancer comes into contact with the timing cover while the engine is running, it will fracture and damage the cover and potentially other surrounding parts. The harmonic balancer should be inspected at every service.

An engine Oil leak may develop from the PCV vent housing on the valve cover and/or the inspection plate on the front of the engine.

The electrical connector at the automatic transmission may leak fluid. Over time leaking fluid could migrate through the wiring harness and damage the transmission control module. If that happens a new harness and control module may be necessary to correct the problem.

The ESP and BAS warning lights may illuminate due to a failed brake light switch. Replacement of the failed switch should correct this concern.

The brakes may begin to squeak at about the 50 percent wear point. This is due to the size and material used for the brake pads and rotors.  The brake rotor surfaces become uneven, causing a lip to form at the outer edge. This will generally require replacement of the rotors when the pads are worn (pad life varies depending on driving style and terrain).

Leaks may develop from the differential cover and/or seals on high mileage or older vehicles. Our technicians recommend a complete reseal of the differential unit if these leaks are addressed.

A vibration felt through the center floor of the vehicle can be caused by cracked and/or shredded driveshaft flex discs, resulting in excessive driveshaft movement. If not repaired, damage to the driveshaft center support bearing, transmission, or differential can occur.

As brake fluid becomes dirty over time, it can cause a failure of the anti-lock brake system (ABS) modulator assembly. Our technicians recommend a complete brake system flush every two years to help prevent this issue.