Objective:
Checking Operation of the Knock sensor.
Measurement:
Plot of voltage at the signal output of the Knock sensor.
Preparation:
Switch off the engine and ignition.
Connections:
| INPUT A | COM/TRIGGER | INPUT B |
|---|---|---|
| Connect the red measurement lead to pin 1 of the X10 wiring harness connector. Connect the black ground lead to ground. |
The signal frequency of the knock sensor depends on various criteria and cannot be used to assess the operation of the sensor.
It can be assumed that the knock sensor is working properly, when the signal plot is an attenuated oscillation.
The amplitude is directly dependent on the impact magnitude and can likewise vary within broad limits.
Procedure Tech 31:
- 1. Download the Reference curve.
- 2. Use a metal object (e.g. a hammer) to strike the engine block in the vicinity of the knock sensor. Regardless of the engine type the following areas are particularly suitable: Below the bolt used to fasten the alternator to the engine block, flat surfaces on the engine block at the front or rear and the engine mounting (use a metal extension if necessary).
