SL 600 (129.076) V12-6.0L (120.981) (1995)
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Knock Sensor
CONSTRUCTION
The knock sensor (C) consists of a housing (3) a piezoelectric crystal (4) mounted on a threaded sleeve (5) between two connector strips (6). One
side of the assembly is fitted with a damping weight (7) and spring washer (8) secured by a nut (9).
OPERATION
The four knock sensors (two A29 and two A30) are subjected to vibrations generated by knock. The vibrations cause a small distortion on the
surface of the piezoelectric crystals, which consequently generates a small voltage. This voltage is read by the EZL/AKR control module. The
control module retards the ignition point for an individual cylinder by 3° crankshaft angle per ignition cycle (Max. of 12°). The knock control
system develops its maximum ignition retard of 12° crankshaft angle at a coolant temperature of 194°F.
