PeachParts Mercedes-Benz Forum - O2 sensor electronics testing

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Quote:

Originally Posted by emerydc8 (Post 1658612)

I went back and re-read your Menu #24 and picked up your comment about the ETA making a mechanical noise when testing it. Then I remembered that there was normally a high-pitch humming noise coming from it when I would turn the key on without starting the engine. I guess that's the motor resetting itself.

During my recent saga w/ the ETA, it reset when reading the EA module (pin 7). Based on that, I was mostly prepared to replace the ETA.
When the NSW (S16/3) was replaced, the 'sounds' returned . . :)

Quote:

Originally Posted by emerydc8 (Post 1658612)

I turned the key off and on about five or six times and every time I turned the key on, the buzzing would continue until I disturbed the wire that went into the ETA. Then I went to the link on your site where the guy shows how he rewired his ETA, because Mercedes used that same great wire they used on the engine wiring harnesses. http://v12uberalles.com/throttle_actuator_rewire.htm I realize now that the problem is probably bad insulation in the wiring--at least the wiring going into the ETA, and probably inside the ETA as well.

Don't wiggle that cable too much while hot . . you could end up blowing a module . . . Pete's DIY article is a 'treatise' on fixing the ETA!

Quote:

Originally Posted by emerydc8 (Post 1658612)

The problem first appeared after I unscrewed the canon plug and, if I had to guess, I would say the wiring is broken between the canon plug and the point where the wiring mount bracket bolts into the manifold with an Allen bolt (second picture)

As Mike pointed out that's the MAF connector and that's, for me, is a good spot to check the engine wiring harness; it only takes a few minutes to do this and if you haven't, you may want to do this.

After twisting the 'cap' loose, use an sharp knife (Xacto) and carefully cut the sheath being careful not to cut the wires inside. Once those wires are visible, you will know the 'state' of the wiring harness. If those are bad, so is the rest of the wiring harness . . . . independent of the ETA wiring.

Quote:

Originally Posted by emerydc8 (Post 1658612)

Rather than try to rebuild it myself, I was looking at the prices at the Jaytan link on your site and, of course, my ETA (000 141 78 25) would be among the most expensive ($799 minus $100 core). I think you mentioned that a new one wholesales at the dealer for $750. I'm thinking it would be better to get a new one.

That was a "very-special" price for yours truly! And is not available to me today. Probably looking at $1100 or so. . . just a wag!

Might be better to check out either Beckmann (more expensive) or Jaytan. If you take it off, they can test it provided you don't need that car.

On the other hand, Jaytan prices look attractive, so just getting a refurbed unit might be the easiest solution.

I'll check around on some prices. If you look at the pictures, I was pointing to the ETA (under the MAF) and the wire leading to it with the tip of a long screwdriver. The MAF plug obviously made its way into the picture. I replaced my wiring harness a few months back. It doesn't look like fun trying to get the ETA out between the manifold.

Do cars with the ASR option have the same mechanical throttle linkage as non-ASR cars? (specifically, the linkage in the picture).

Quote:

Originally Posted by emerydc8 (Post 1658901)

If you look at the pictures, I was pointing to the ETA (under the MAF) and the wire leading to it with the tip of a long screwdriver.

Yes you were pointing and touching the ETA . . . my error!

Quote:

Originally Posted by emerydc8 (Post 1658901)

I replaced my wiring harness a few months back.

Well, then solves that problem nicely!

Quote:

Originally Posted by emerydc8 (Post 1658901)

It doesn't look like fun trying to get the ETA out between the manifold. Do cars with the ASR option have the same mechanical throttle linkage as non-ASR cars?

It isn't exactly the easiest thing to get out. . the twisting and turning gets it out once everything has been removed.

Not sure but the ASR option is in the ABS module. I think they are the same?? Once you get it out, you will see the PN.

Jim, your WAG wasn't far off. I couldn't find the part on MercedesShop.com, but Duval wants $1,068 for an ETA.

FYI: the old style ETA plug (90 deg) and cable is available separately from Germany very cheap (compare to ETA). If you want you could replace the cable and hope for the best. p/n 140 540 15 81. I ordered them couple years ago from Roy Tucker. http://rrparts.com/
Mike

I will certainly keep that in mind, even if I decide to get a new ETA and fix my old one. But, rebuilding the connector that goes into the ETA seems to be a complex job (it takes up the whole last quarter of the page in this link http://v12uberalles.com/throttle_actuator_rewire.htm).

BTW, my cruise control is working again. Go figure.

Quote:

Originally Posted by myarmar (Post 1658938)

Good info . . . will add into MENU#24 since the cable. . . all things considered . . . is THE toughest part of the job esp when trying to re-use the old connector. Tnx, Mike

But keep in mind this p/n 140 540 15 81 is for the older 90 degree connector from I believe 92 - 93 cars. The newer ETAs have straight connector with different pin arrangement.

It's hard to tell whether any soldering would be required where it goes into the ETA. If I just wanted to change the cable harness alone, does anyone know whether I can just pull the old cable out or is it more complex than that?

Myarmar, when you refer to the 90 degree connector, is this what you're referring to?

From this picture, it looks like maybe there are pins that go all the way into the ETA.

http://v12uberalles.com/PassSide18.JPG

Yes, that connector. Should have p/n on it. And yes soldering would be required. check JimF pictures of the ETA internals.
Look at the picture Jim attached in post #42. Connector and black cable is p/n 140 540 15 81.
It goes inside ETA and each wire soldered to the PCB there.
Mike

Thanks. This is all helpful information. Last week, I didn't know what the ETA was, where to find it, or whether my car even had one.

Quote:

Originally Posted by myarmar (Post 1659149)

But keep in mind this p/n 140 540 15 81 is for the older 90 degree connector from I believe 92 - 93 cars. The newer ETAs have straight connector with different pin arrangement.

Yes, I understand . . . I've added to MENU#24 . . .

Quote:

Originally Posted by emerydc8 (Post 1659157)

Check Pete's link for good picture of the frayed wires coming in from the cable. You will need good soldering skills and be able to match wires and pins. Not a trivial task . .

Here's a follow up on the ETA wiring harness. I was able to order one through the dealer for $18.00. It had to ship from Germany. It looks like some soldering will be required where it goes into the ETA (11 wires total). I think I'll wait until my cruise control goes out again before I screw with it.