I understand that I can check the Lambda using a digital voltmeter connected to the diagnostic plug. Do you know the pins that I should check across and what values should I look for?

Thanks John Lee

The only Meter that I am aware of you can use is the Fluke 87 and 88. I have a bulletin at work that shows how. The pin is #3 but you have to do some special things to get the right reading. I'll see if I can dig it up for you.

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Benzmac:
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Were you able to find the procedure? I have watched MB mechanics just plug in the multivoltmeter and read it out.I don't recall that they went thru any specific process. If pin 3 is it what is the other pin, perhaps for ground?

I am still seeking a response to the original question that was only partially responde to with a promise for more to come.

Thanks, John

To read the signal you must have a lamda meter or volt meter that has a "duty cycle" feaure. The signal the the ECU sends is a processed signal, not a voltage signal. As Benzmac said use pins # 3 & 5, w/fluke 80-series in duty cycle mode