Mercedes-Benz E320 4MATIC Problems

RepairPal has identified the most common problems with the Mercedes-Benz E320 4MATIC as reported by actual vehicle owners. We'll tell you what the problem is and what it'll take to fix it.

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40
Known Problems

This vehicle has sensotronic brake control (SBC). If the SBC light on the dash illuminates, have the brakes checked. If the SBC is not working, limited brake pressure is delivered to the front brakes, increasing the distance it takes to stop. The SBC hydraulic unit has a specific service life programmed into the control module; follow the manufacturer's recommended service procedure for proper maintenance of the SBC.

Mercedes Benz E320 4Matic models manufactured between 2005 and 2009 may have engine oil seeping or leaking from the back of the cylinder heads. This is commonly misdiagnosed as leaking valve covers.

On the back of the cylinder heads there are three, in total, plastic expansion plugs that plug access ports to the camshafts. These plugs are well known for seeping oil, and leaking if left unattended. The oil will run down the back of the engine and eventually make it to the ground. 

Replacement of these three plastic plugs is extremely simple, and should be done as regular maintenance. The recommended interval for replacement is every 60,000 miles.

Irregular and premature tire wear can be caused by the lower control arm bushings cracking, resulting excessive movement at the control arm pivot point. Ball joints can also wear out prematurely, causing similar tire wear symptoms. I some cases it may be necessary to replace the lower control arm, including bushings & ball joint to correct this concern.

High mileage or older vehicles commonly develop leaks from the differential seals and/or cover. Our technicians recommend a complete reseal of the differential unit whenever these leaks are repaired.

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

Water can damage the weight sensor in the front, passenger seat, causing the SRS (airbag) light to illuminate. There is an electrical component in the seat cushion susceptible to fluid damage. Any spills should be dried up immediately in order to try and prevent damage to the sensor.

The engine may develop a stalling and/or no start condition due to a failed crankshaft position sensor.

Failed spark plug wires and/or ignition coils can cause intermittent misfires (rough running); the Check Engine Light may also illuminate. Diagnoses of the ignition system will be necessary to determine which components are at fault.

Bad spark plug wires can cause misfires; the Check Engine Light may illuminate.

The mass air flow (MAF) sensor tends to fail. The engine air filter should be replaced when the mass air flow sensor is replaced; a dirty filter can allow debris to damage the new sensor.

The evaporator temperature sensor can fail, causing the AC compressor not to cycle. If the AC compressor does not turn on, the AC system will not blow cold air. If the compressor is stuck on, the air will be very cold at first, before warming up.

Catalytic converter failure is common and may cause a Check Engine Light to illuminate.

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.

A malfunctioning HVAC blower motor regulator can cause the blower motor to operate below the requested speed or not at all. Updated regulators are available; the blower motor and cover need to be replaced at the same time to upgrade the system.

A vibration felt through the center floor of the vehicle can be caused by driveshaft flex discs, which crack and shred, causing excessive driveshaft movement. Not repairing these can cause damage to the driveshaft center support bearing, or, in the worst case scenario, damage to the transmission or differential.