944 Turbo

The knock regulation system can be checked with a test adapter and LED. Insufficient engine power may be caused by 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 will increase to more than 1500 RPM. If the LED remains dark, there is no fault in the knock regulation system. If the LED is on continuously, there is a problem. The problem can be found by dropping engine speed to below 1500 RPM. The LED will start flashing trouble codes.