Mass Air Flow Sensor

Replace the Mass Air Flow (MAF) sensor on the 2007-2013 Mercedes-Benz S65 AMG M275 V12 BiTurbo engine to restore proper air intake metering and engine performance.

Warnings

Tools required

Parts

• Mass Air Flow Sensor × 1 — A000 094 05 48 or OEM equivalent
• Air intake duct O-ring seal (if damaged) × 1 — Use OEM specification

Preparation

1. Park vehicle on level ground and engage parking brake
2. Turn ignition off and remove key from ignition
3. Allow engine to cool for at least 15 minutes
4. Open hood and secure with prop rod
5. Identify which MAF sensor needs replacement (driver or passenger side intake tract)

Procedure

1. 1

   Disconnect MAF sensor electrical connector
   Locate the MAF sensor in the intake duct between the air filter housing and throttle body. Press the release tab on the electrical connector and carefully pull the connector straight off the sensor. Do not pull on the wiring harness itself.
2. 2

   Loosen upstream air intake clamp
   Using a flathead screwdriver or appropriate tool, loosen the hose clamp securing the air intake duct upstream (toward air filter) of the MAF sensor. Do not remove the clamp completely, just loosen enough to allow movement of the duct.
   Torque spec

   Air Intake Clamps3 Nm (2 lb-ft)
3. 3

   Loosen downstream air intake clamp
   Loosen the hose clamp securing the air intake duct downstream (toward throttle body) of the MAF sensor. Again, loosen sufficiently to allow duct removal but clamp does not need to come off completely.
   Torque spec

   Air Intake Clamps3 Nm (2 lb-ft)
4. 4

   Remove MAF sensor mounting screws
   Using a T25 Torx driver, remove the two or three screws (depending on year) securing the MAF sensor to the intake duct housing. Keep these screws in a safe place as they may be reused if in good condition.
   Torque spec

   MAF Sensor Screws3 Nm (2 lb-ft)
5. 5

   Extract MAF sensor from intake duct
   Carefully pull the MAF sensor straight out of the intake duct housing. Inspect the O-ring seal on the sensor body for damage, cracks, or deterioration. If the seal remains in the duct, remove it with your fingers.
6. 6

   Clean intake duct sealing surface
   Using a clean microfiber towel, wipe the sealing surface inside the intake duct where the MAF sensor seats. Remove any dirt, oil residue, or debris. Do not allow any contaminants to enter the intake tract toward the engine.
7. 7

   Install new MAF sensor
   Verify the new MAF sensor has a proper O-ring seal installed. Carefully insert the new sensor into the intake duct housing, ensuring proper alignment of the mounting screw holes. The sensor should seat flush against the duct.
   ⚠Ensure the MAF sensor is oriented correctly with the arrow on the sensor body pointing in the direction of airflow (toward engine)
8. 8

   Secure MAF sensor mounting screws
   Install the MAF sensor mounting screws and tighten to specification using a torque wrench. Tighten in a cross-pattern if there are more than two screws. Do not overtighten as the sensor housing is plastic and can crack.
   Torque spec

   MAF Sensor Screws3 Nm (2 lb-ft)
9. 9

   Reconnect air intake ducts
   Ensure both upstream and downstream intake ducts are properly seated on their connections. Tighten both hose clamps to specification, ensuring even pressure around the circumference of each duct.
   Torque spec

   Air Intake Clamps3 Nm (2 lb-ft)
10. 10

    Reconnect MAF sensor electrical connector
    Push the electrical connector onto the MAF sensor until you hear and feel a positive click indicating the locking tab has engaged. Gently tug on the connector to verify it is fully locked in place.

Reassembly

1. Verify all electrical connections are secure and properly locked
2. Double-check that both air intake clamps are tightened to specification
3. Ensure no tools or parts have been left in the engine compartment

Verification

• Start the engine and verify it idles smoothly without hesitation or rough running
• Check for any air leaks around the MAF sensor and intake duct connections by listening for hissing sounds
• Rev the engine gently to 2000-3000 RPM and verify smooth acceleration and deceleration
• Use a scan tool to verify there are no MAF-related fault codes present (P0100-P0104 series)
• Perform a test drive to confirm improved throttle response and no check engine light illumination
• If available, compare MAF sensor readings on scan tool to specifications (typical idle reading: 3-7 g/s per bank)

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