300SL (129.061) L6-3.0L (104.981) (1991)
Impulse Counter/On-Board Diagnostic Connector
When the start-button on the impulse counter is depressed for 2 to 4 seconds (ignition ON), the impulse counter will begin a impulse readout. The cause
of the malfunction(s) will be indicated by the number in the impulse counter window. Fault codes will be displayed in ascending order. If several fault
codes are stored, the next fault code will be displayed by pressing the start button again. If no additional fault codes are stored, the first number will
reappear.