Oxygen Sensor Signal: CODE 17
 

My check engine light came on after I replaced my EHA with a used one. My previous EHA was bad and would leak. The one I replaced it with does not leak. I bought 2 used and no matter what one I put on I get the CODE 17. Someone suggested that it might be the O2 sensor itself, so I went out and bought another and put it on seeing how mine was last changed 41k miles ago, but I still get the CODE 17 even with the new O2 sesor. Any suggestions on how to remedy this?

Most likely the fuel mixture need adjustment now.

Either too rich or lean & the O2 sensor doesn't have control of the mixture.

Do you have a DMM with duty cycle ability?

I don't have a DDM, what is it and how do I adjust the mixture?

O2 sensor reading?
 

I bought a multimeter today and this is what I found at the O2 sensor ecu wires:

green wire: 0.4v engine off
both white wires: -0.4v engine off

green wire: 0.4v engine on
both white wires: 11.7v engine on.

These are the wires under the passenger side mat connected to the computer of the car.

I tried testing the wires to the actual O2 sensor and didn't get any reading both with engine on and off.

This is my first time ever using a multimeter. Are my readings correct? If not how do I fix them? These problems only started happening after replacing the EHA with a used one.

On my 1992 500E the ECU sends .45 volts as a simulation of the O2 sensor output until it warms up. There after it cycles between a high value and a low value somewhere between 0 and 1 volt in order to control the air fuel ratio between say 12 to 17 depending upon engine operating conditions.

Ok, so I believe the Code 17 has been cleared....but I'm not exactly sure which solution clered th code. Here is what I did:

1) I originally bought a new O2 sensor that I spliced into the fitments of my oe so I took the 2 heater wires (white) and I interchanged them with one another (not sure if that made any difference since they are both the same)

2) I slightly adjusted the fuel mixture tower. There was I small steel ball in the top opening and on the side of the tower was a small hole which allowed me to stick a small hex key in and lift the ball out. The whole procedure took less than a minute.

3) I boutght a used EGR valve and replaced mine. This was a pain since my valve was pretty much fused to the damn manifold. 20+ years of heat! Once I got it off, I cleaned the area around it, scrubbed the gasket with a wire brush, sprayed the thread holes with silicone and then I decided to coat the gasket, the bolts and nuts, all the threads of the holes, and the bottom rim of the EGR valve with dielectric/anit-seize grease (highly recommended if someone has to replace their EGR or anything on the manifold)

4) I swapped out one of the EHA valves with the other one I bought.

Drove the car all day today and no CEL and it usually comes on in 30 minutes after driving, so I think I'm set.

Cheers!