Mercedes-Benz W211 (E-Class 2002–2009, including the S211 estate): common faults, maintenance guides and repair tips.
The transmission oil is cooled by engine coolant in a small cooler. Its seal can fail, which lets coolant (glycol) mix into the transmission oil. The ...
The most common cause is the torque converter lock-up valve (KYB valve), located on top of the transmission conductor plate. The symptom is worst when...
The oil container must carry the Mercedes-Benz approval MB 236.10 or MB 236.14. The newer 236.14 also suits the 7-speed transmissions, but it brings n...
The most common cause is the transmission's conductor plate, which has the speed sensors built into it. Fault codes often point to a speed sensor, for...
A slight jerk when cold is normal, but a strong one often points to old or wrong oil, or the wrong oil level. If the fault is mechanical, the symptom ...
The battery control module monitors the voltage of the main battery and the auxiliary battery. When energy is being used quickly, it switches off comf...
The auxiliary battery is a small extra battery that supplies power to the SBC brake control. It is in the engine bay near the bulkhead, under the air ...
Culprits found have included the driver's electric seat control box (drawing over 1 A with the engine off) and, on the estate, a broken wire of the fo...
With the car running, the terminal voltage should stay steady at about 13.8-14.5 V. The resting voltage of a full battery is about 12.6-12.7 V. The vo...
Drive the car into the garage, take the key out of the ignition and switch off the consumers. Wait before disconnecting the terminals so that the car'...
It is a fault message from the SBC brake system (Sensotronic, electrohydraulic brake). The cause can be a leak, air or a blockage in the brake circuit...
The most common causes are a slide pin that does not move freely in the caliper bore, and a sticking piston. Hardened grease in the slide pin bore sto...
The most common cause is an air leak. The air spring may be cracked or its protective bellows aged, or the aluminium at the joint between the spring a...
The cause is often electrical: a blown fuse, a faulty relay, a loose power connector or a broken wire. Other causes are a clogged air filter, a damp d...
The rear level sensor's lever is attached to the rear anti-roll bar link. If the link comes off, the sensor arm drops down and the car thinks the rear...
The most common sources are the lower control arm ball joint, the anti-roll bar joints and bushings, the thrust rod mounting, the upper ball joint and...
Only if the upper ball joint is held on with bolts and nuts. On the original control arm the ball is cast into the arm, so the whole control arm is re...
The bushing is the outermost joint of the rear lower control arm. Lift the lower control arm off the ground and rock the wheel. Play can be hard to de...
The most common causes are the propshaft centre bearing bracket, the propshaft universal joint, the rear bearings or the differential. The rear end ca...
The differential needs an MB 235.7-approved synthetic oil, which has replaced the older mineral oil (235.6). The most common recommendation is viscosi...
Symptoms are a fuel smell inside the car, gurgling at the base of the injector and uneven running. Leak-back affects starting most, and at worst the c...
The most common causes are the quantity control valve next to the high-pressure pump and injector leak-back. The rail pressure sensor or an injector t...
Limp mode occurs when the boost pressure requested with the accelerator pedal and the actual boost pressure differ too much. Code 2348 means too low a...
The amount of air measured by the mass air flow sensor (MAF) is greater than the engine control expects. The cause is often in the EGR system (exhaust...
The most common cause is the glow plug relay, whose internal conductor has burned or whose output stage is faulty. The relay is on the left side of th...
The most common cause is a seized heater water valve. It can keep the air hot even when cold is requested, or prevent heat altogether. Another cause i...
The most common cause is the levelling motor behind the headlight unit. It is a stepper motor that finds its home position at start-up by driving to i...
The most common cause is a single faulty sensor. The fault is found with a diagnostic tool that shows the distance of each sensor separately, and the ...
The cause may be a broken tailgate control unit in the middle inside the tailgate. As the fault progresses, the blind also stops working and the batte...
The lights come on when the car receives an incomplete or implausible speed signal from a wheel. The cause is the sensor or the magnetic ring it reads...
The fluid specification must be MB 345.0. For the change, the return hose is disconnected and the engine is run until the old fluid has drained out, w...