Check Basic Position Of Camshafts - AR05.20-P-6010CD

ENGINES 651 in MODELS 166, 172, 204, 207, 212, 218, 221 

Shown on engine with belt pulley 

	Remove/install
1	Remove transmitter key	On vehicles with code (889) Keyless Go, press Start-Stop button repeatedly until the ignition is switched off.
2	Remove cylinder head cover trims
3	Unscrew oil filler cap
4	Remove camshaft Hall sensor		AR15.10-P-2000CD
5.1	Rotate engine at crankshaft using a counterholder in direction of engine rotation and place piston for cylinder 1 at top dead center (ignition TDC)	Except code (B03) ECO start-stop function The engine must not be turned back. The timing chain can skip otherwise and can cause engine damage. The 0° marking on belt pulley/vibration damper (2) must align with marking on cylinder crankcase (3). Counterholder	Figure
5.2	Rotate engine at crankshaft using a suitable tool in direction of engine rotation and place piston for cylinder 1 at Top Dead Center (ignition TDC)	With code (B03) ECO start/stop function The engine must not be turned back. The timing chain can skip otherwise and can cause engine damage. The 0° marking on belt pulley/vibration damper (2) must align with marking on cylinder crankcase (3).
	Checking
6	Check setting of the intake camshaft	The marking on the intake camshaft (A) must coincide with the marking on the camshaft bearing cap (B). If the marking on the intake camshaft (A) is not visible, turn the crankshaft through one revolution, set to 0° and check again. Adjust the camshafts if the markings (A, B) still do not match. See: ↓ Set basic position of camshafts	AR05.20-P-6020CD
7	Check setting of exhaust camshaft	The marking on indexing wheel of the exhaust camshaft (D) must coincide with the marking in the bore for the camshaft Hall sensor (C). Adjust camshafts if the markings (C, D) still do not match. See: ↓ Set basic position of camshafts	AR05.20-P-6020CD
8	Install in the reverse order

Fig 1: Identifying Counterholder (651 589 00 40 00)

Courtesy of MERCEDES-BENZ USA