Mercedes-Benz W212 (E-Class 2009–2016, including the S212 estate): common faults, maintenance guides and repair tips.
Often the cause is the transmission fluid: too little, old or poor quality. With a low fluid level a gear can engage before pressure is sufficient, an...
The fluid specification depends on the car. Cars with start-stop or equipment code A89, which requires low-friction fluid, need class 236.15 fluid. Ot...
Common causes are adaptation values that have drifted off (the driving style the transmission has learned), too little or old transmission fluid, and ...
The car limits power (limp mode) when boost pressure deviates from the target. The cause can be a leak on the intake side, a cracked charge air hose, ...
1. Take the keys out of the ignition and move the keyless key a couple of metres away from the car. 2. Wait for the systems to go to sleep. 3. Disconn...
Most often the cause is a fault in the electronic ignition lock: the key recognition does not work properly and the automatic P function engages. The ...
The most common cause is snow or ice in front of the front radar. In that case, besides Distronic, PRE-SAFE Brake and blind spot assist messages often...
It depends on the engine. On the OM642 the sensor is in the engine bay on the left of the turbo near the bulkhead, part number A6429050100. On the S21...
Often the fault is a small relay in the fuse box. The relay can close late or stay stuck, so the starter does not work or starting is delayed. Replaci...
Common causes are the anti-roll bar links (drop links) and body bushings, and worn front control arms. The cause varies from car to car, so a single p...
Air either cannot build pressure or cannot flow to the air springs. The cause can be a leaking or stuck valve block, a faulty level valve, the compres...
Check the sensor rods and their ball joints. They can rust or get dirty and seize, and a seized rod can bend the sensor's mounting plate so that the s...
The codes point to the electrical circuit of the air suspension pressure relief valve. The fault does not always mean the valve itself is broken; ther...
Most often the cause is a leaking air spring, which leaks especially in the cold. If the rear drops clearly on one side only, the leaking spring is on...
First check whether the compressor is getting power. Its power runs through the fuse box next to the battery under the bonnet, and the small high-curr...
The code does not always mean a faulty mass air flow sensor (MAF). The cause can be a crack in the charge air pipe (e.g. on the underside of the pipe ...
Typical leak points are the fuel filter housing and the water pump. On the OM651 the filter housing sits between the thermostat and the cover, and its...
The most common cause is moisture. The radar housing seal or the glued cover does not withstand frost or salt water, so water and salt oxidise the int...
One cause is a blocked heater core. Silicate from the expansion tank (an additive that reduces cavitation) can get into circulation with the coolant a...
The alternator brushes usually wear out first, and replacing the brush set may be enough. The alternator can also give a fluctuating voltage, which ma...
The most typical leak points are the oil filter housing, the oil cooler next to it and the valve cover. Sometimes the crankshaft seals also leak. Repl...
The red lights indicate that the whole sensor system is out of use because of a sensor fault. Even one broken sensor is enough. The fault can be read ...
The cause can be the high-pressure pump's fuel metering valve, the filter or the injectors. The fault is often in the injectors, which leak pressure i...
The pressure pipe does not have to be removed completely. Loosen the three screws of the mounting frame and the pipe connections and tilt the filter t...
Symptoms are knocking, smoking, the engine warning light, and uneven running at idle and under acceleration. There are many symptoms and causes, so a ...
The original electrically controlled thermostat has part number A6422002215 and opens at 92 °C. The version that opens at 87 degrees is the wrong mode...
A reddish tint indicates the bulb is reaching the end of its life; replace both bulbs then. If the light does not work at all, the fault may be in the...