Mercedes-Benz W204 (C-Class 2007–2014, including the S204 estate and C204 coupe): common faults, maintenance guides and repair tips.
Timing chain stretch is a known weakness of the M271 engine, and the chain can jump without warning. Replacement is recommended in good time, usually ...
Symptoms can be mild: poor starting, uneven or knocking idle, lack of power after a long drive or a smell of burnt rubber. An injector fault does not ...
The fault can put the car into limp mode and light the engine warning light. Codes include P2453, P2454, P2455 and P244B. The cause can be the sensor ...
The cause varies from car to car. Most often the fault is caused by the boost pressure sensor, a split charge air hose or intercooler hose, or a vacuu...
The cause varies from car to car. Common ones are leaking injectors, a faulty glow plug relay, a coolant temperature sensor giving wrong information a...
Possibly. The glow plug relay, or glow plug control unit, can fail, and new glow plugs alone then do not fix the fault. A faulty relay can also burn o...
The cause varies from car to car and transmission to transmission. Possibilities are old transmission oil, incomplete clutch filling when cold, sticki...
The cause varies. Often the fault is in the conductor plate, i.e. the transmission's electrical connection, and second most commonly in the transmissi...
A transmission built after June 2010 (7G-Tronic plus, option code A89) takes the bluish MB 236.15 oil. An earlier transmission takes the red MB 236.14...
The cause is often the dual-mass flywheel or the release bearing. A broken dual-mass flywheel can let grease onto the clutch disc, so the disc burns a...
The cause is usually a circuit or relay that stays on, so the car does not go to sleep mode. Examples are a relay feeding the engine that stayed on af...
According to the spare parts data, the original battery is an AGM type (VRLA, valve-regulated lead-acid battery). Still, check your own car's battery ...
Charging voltage is measured with the engine running, and it should be slightly over 14 V. An AGM battery needs an even higher voltage. If the reading...
The cause varies. The most common is a weak or faulty starter battery, in which case the ECO symbol stays lit and the engine does not stop. Also neede...
Often the fault is in the electric steering lock and not in the ignition switch. A typical part is the steering lock motor. Symptoms can be that the k...
The fan goes to full speed when its control signal is missing. The cause can be a faulty A/C pressure switch or pressure sensor, a chafed or corroded ...
A common cause is a thermostat that keeps the coolant circulation open. When the temperature stayed at about 75 degrees in freezing weather, a new the...
On the OM651 engine the most common leak points are the water pump and the oil filter housing base joint. The pump can leak so little that no leak is ...
The most common cause is the blower motor: the brushes wear out, the bearing wears or the fan wheel warps. Replacing the motor usually fixes the fault...
The cause varies. The most common are a faulty pressure sensor, also called the pressure switch, a seized compressor and low refrigerant. Topping up r...
The most common cause is the connector of the tail light ground wire, which heats up because of poor contact and melts. Replacing the bulb does not he...
The cause varies, but often the fault is poor contact in the lamp connector or in the tail light ground wire, which can corrode or come loose from the...
Yes. A rusted or broken ABS tone ring gives the sensor a weak or intermittent signal. The result can be ABS and ESP lights, transmission jerking and f...
The codes indicate an internal fault in the ESP control unit (N30/4). The ESP and ABS lights often come on when the speed exceeds about 20 km/h, and t...
The cause varies from car to car. Common ones are control arm bushings, a loose anti-roll bar link nut, the strut top mount rubber or bearing and the ...
The cause varies from car to car, but often adjusting the front caster angle (the lengthwise tilt of the wheel) with adjustment bolts helps. Sometimes...
The open end of the subframe lets moisture and dirt in behind the bushing, and the subframe can also rust from the inside. It should be cleaned at eve...
The adjustment is reached through the rear seat. The front edge of the seat is lifted and the seat is moved back, which frees the hooks at the rear ed...
The cause can be a faulty relay in the boot fuse box; replacing the relay fixed the fault. In the S204 estate the relay is on a circuit board behind t...