I just digested all the KE3-Jetronic System from landiss.com as it pertains to my 1989 560 SEC's.

I did the lambda on/off duty cycle ratio test at the X11 diagnostic connector between pin 2 and pin 3 with with ignition on and engine off I established
I have the "California Connector".

If I understood Dan@landiss the Calif car cannot perform the lambda on/off ratio duty cycle test, at least not at diagnostic connector X11.

As for diagnostic connector X92, I can get the LED light to either stay constant on or constant off.
I cannot get LED to flash.

Is there a multi-meter test to determine the status of the oxygen sensor??

Thank you for your time and consideration.
mitch mabee
mitchmabee99@Gmail.com

1989 560 SEC

To read the duty cycle on that car the ECU must go into a diagnostic mode 1st.

To put the ECU in that mode press the button on the diagnostic connector & hold it 3 seconds. When the LED blinks once then you can read the duty cycle at the round connector.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator