944 Turbo

The control unit of the knock regulator has a memory for the disturbances occurring during operation. The knock regulation system can be checked with a test adapter and LED in the case of assumed or determined disturbance or malfunction of components in the knock regulation system. Insufficient engine power can be low charging air pressure, engine knock or ignition timing not conforming with the test values.

When the test adapter is connected to the diagnosis plug, the engine speed is now increased to more than 1500 RPM. If the LED remains dark, there is no fault in the knock regulation system or its components. If the LED is on continuously, there is a problem. The problem can be found by dropping the engine speed to a value below 1500 RPM (idle speed). The LED will now put out interrupted light signals, which are easy to recognized as flashing codes.