Oxygen Sensor wire to CIS Unit Repair - PeachParts Mercedes-Benz Forum

slk230red · #7 05-24-2009, 05:32 PM

Quote:

Originally Posted by JamesDean

Hm... I'll have to try that trick you said because, as per the FSM, I got no continuity between the o2 control wire and any of the pins on the cise connector. I even checked with a known working car (90' 300SE) and none of its pins are connected to the o2 sensor.

I dont believe that i have to put it into diagnostic mode for duty cycle. A friend of mine who was helping me adjust it said that I didnt need to. Also, it was reading duty cycle numbers fine prior to something causing it to go to .09v=100% dc. I just checked my friend 300SE and it reads duty cycle fine.

I could not read Duty Cycle on my '93 2.3 so I posted a thread on this site. Steve Brotherton stated that I had to put my '93 into Diagnostic Mode to read duty cycle.....he was correct. Maybe yours is different.

Duty Cycle 0.0%

From Manual:

@1988 California and
@1991 with diagnostic trouble code
storage:

The CFI control module must be switched over
to output of on/off ratio because the signal for
the diagnostic trouble code (DTC) display is
output as priority.
The output of the on/off ratio is performed once
all the DTCs have been read out and the start
button of the impulse counter scan tool or the
non-locking switch on the diagnostic connector
(California version only) is then once again
pressed (see section m).
The % readout now fluctuates when the engine
is running at normal operating temperature and
there are no DTCs.