Porsche 944 - Manual (Page 29)

944 Maintenance, Self-diagnosis
03
Knock detection
Before knock detection is carried out, error
diagnosis must first of all be performed to
guarantee that no electrical error has
occurred
in the area of the knock control and the
knock
sensors.
Knock detection should not be carried out if
the customer has complained about poor
out-
put or too high a consumption, for instance.
Condition:
The engine most be at operating
temperature
during the test. Testing most be carried out
during a test drive or on the roller test stand.
Knock detection
Engine at operating temperature
While the engine is running, simultaneously
press the yellow and the green key until the
knock detection function symbol appears
on the function display.
Display:
The tester is new in knock detection mode.
Note:
Normal driving is a prerequisite for the
test drive (roller test stand).
Start the test drive (roller test stand).
Press the green key until the clear symbol
appears on the function display.
Display:
Knock detection
Printed in Germany - XVI, 1987
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