Mercedes-Benz W210 E-Class MAF Sensor Replacement

The mass air flow sensor (MAF) is located inside the engine compartment and is used to measure the amount and temperature of air that is entering the engine at any one time. Older style meters used on fuel injection systems in the 1980s measured air volumetric flow, which worked fine but then you also needed a separate sensor to figure out how cold or dense the air was. The mass air flow sensor senses the total amount of air passing the sensor and allows the fuel injection system to adjust the fuel mixture to compensate for cold weather and/or high altitude conditions. The MAF also incorporates an internal intake air temperature sensor which measures the temperature of the intake air.
The first indicator that you might have a problem with the MAF is the presence of a check engine light (CEL) on your dashboard. The check engine lamp can be caused by a wide variety of problems with the engine: you need to read the codes from the computer to get a starting clue as to what the problem is. However, the engine will not be operating at peak efficiency, and you will most likely experience a loss in power and a decrease in gas mileage as a result. It's best to get the problem taken care of relatively quickly, as running the engine in this condition can potentially cause damage to other components like the catalytic converters.
The computer will know if something is wrong with the MAF because it will compare the values being output by the sensor to "expected" values that it should be receiving. This common-sense check by the computer helps to diagnose problems with every component in the system. If the MAF becomes dirty and is falsely indicating to the engine that the car is receiving very little air while at full throttle, then the computer will most likely kick back an error code.
Vacuum leaks and other air leaks in the system can cause MAF sensor errors. If you have a crack or leak in your air intake downstream of the sensor, then the MAF will be sensing less air than the engine is actually receiving. If the clamp on the throttle body happens to come loose and fall off, then the MAF will indicate almost no air being sucked through the intake, yet the engine will be sucking air directly from the engine compartment into the throttle body. The bottom line is that you should carefully inspect all of your hoses, clamps and intake tubes for air leaks prior to replacing the sensor.
After you have replaced or cleaned the sensor and cleared the code, you need to go drive the car and see if the code returns. If the same error code appears, then the problem probably lies elsewhere. Most of the time when you have an error code indicating a problem with the mass air flow sensor, it is usually solved by the installation of a new sensor. However, the computer can become confused sometimes and give misleading error messages. Wire harness issues, DME problems, and secondary air injection equipment problems may all give false MAF error codes. At this point, it's best to dive into the factory manuals and start going through the laborious test procedures contained in there.
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Time: 30 minutes
Tab: $400
Tools: Phillips head screwdriver :www.pelicanpar...
Applicable Models: Mercedes-Benz E320 (1996-97) :www.pelicanpar...
Parts Required: New MAF :www.pelicanpar...
Hot Tip: Do not use oiled filters
Complementary Modification: Replace air filter