Remove/install hot film mass air flow sensor - AR07.07-P-1453GZA (ML350, ML550, GL450, GL550)

ENGINE 272, 273 in MODEL 164, 251

Shown on engine 272

Fig 1: Identifying Hot Film Mass Air Flow Sensor Components

G05257631

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

	Remove/install
	Risk of injury caused by fingers being pinched or crushed when removing, installing or aligning hoods, doors, trunk lids, tailgates or sliding roof.	Keep body parts and limbs well clear of moving parts.	AS00.00-Z-0011-01A
	Information on preventing damage to electronic components due to electrostatic discharge		AH54.00-P-0001-01A
1	Turn key in ignition lock to position "0"	Vehicles with Keyless Go, code 889: Press Keyless Go start/stop button repeatedly until ignition is switched off.
2	Remove air filter housing (1).		AR09.10-P-1150GZA
3	Separate electrical connector at hot film mass air flow sensor (B2/5)
4	Disengage right notch (3a) of the hot film mass air flow sensor (B2/5) on resonance intake manifold	Pull right notch (3a) to the outside until it can no longer latch again on resonance intake manifold. Never use force as notches can break off! If notches (3a, 3b) break off, the entire hot film MAF sensor (B2/5) must be replaced.
5	Unlatch left notch (3b) on hot film MAF sensor (B2/5) on resonance intake manifold and remove hot film MAF sensor (B2/5) upwards	Do not damage the grid (A) in the process as it cannot be replaced separately! Never use force as the notches can break off! If the notches (3a, 3b) break off, the entire hot film MAF sensor (B2/5) must be replaced.
	Checking
6	Check gasket (7) between air duct housing (4) and hot film mass air flow sensor (B2/5)	Check seal (7) for damage; replace if necessary.
7	Check right notch (3a) and left notch (3b)	If notches (3a, 3b) are damaged, then the entire hot film MAF sensor (B2/5) must be installed anew.
8	Install in the reverse order
9	Read out fault memory and erase if necessary	Stored faults which may be caused by disconnecting cables or by simulation during test operations, must be erased in the fault memory after completing the work. STAR DIAGNOSIS diagnostic system