Measurements and analysis with the VAS 5051
Knock sensor G61
The knock sensor records the vibrations of the engine during knocking combustion, and passes a signal on to the engine control unit. The engine control unit then sets the ignition point to "Retard". This allows the engine to be driven with different fuel qualities.
The function diagram for the knock sensor is shown on the left.
The electric signal for subsequent analysis by the DSO is measured at the following contacts:
DSO 1 (+)
DSO 1 ()
Contact 1 (signal) Contact 2 (ground)
The function of the knock sensor can be checked from the curve by intermediate connection of an adapter lead from the V.A.G. 1594A test set.
The DSO measuring lead is connected parallel to the contacts 1 and 2 of the knock sensor.
The following curve is obtained:
DSO measuring lead