O2 sensor electronics testing - Page 4 - PeachParts Mercedes-Benz Forum

emerydc8 · #46 10-24-2007, 06:18 PM

Well, I think I found one of the functions of the ETA besides ASR. Since I took the canon plug off with my engine running last week, my cruise control is completely inoperative. Also, I'm getting a DTC 3 on Socket 7 of my 38-pin connector. The code cannot be cleared. I noticed that my idle speed has dropped from about 500 RPM to 250 RPM too. I checked the fuses in the regular box. I don't want to jump to the conclusion that it's a bad cruise control amplifier, since I think the problem originated from my own monkeying with the ETA wiring. Any ideas?

JimF · #47 10-24-2007, 07:19 PM

Simply put . . . you can't do that! EA/CC/ISC and ETA are married together. The "CC" is 'cuise control'.

Don't think you found anything new but you certainly created a DTC!

emerydc8 · #48 10-24-2007, 09:13 PM

Now, if I could just get my cruise control back I promised myself I would never screw with something that wasn't broken.

JimF · #49 10-24-2007, 09:51 PM

Quote:

Originally Posted by emerydc8

Now, if I could just get my cruise control back I promised myself I would never screw with something that wasn't broken.

Some have reported losing the CC when their ETA went bad; for me, I never did lose my CC when mine went bad.

Have you read all of the DTCs from your car??? It would help to show what's what.

emerydc8 · #50 10-25-2007, 01:34 AM

When I checked all the codes yesterday, I got a DTC 4, DTC 6 and (dreaded) DTC 19 on socket 19, along with a DTC 3, 6 and 11 on socket 7. I was able to clear all but the DTC 19 on socket 19 (as expected) and the DTC 3 on socket 7. I know what's causing the DTC 19 and it's probably been there for an half decade. The only remaining code that's a problem is DTC 3 on socket 7, which (I think) is the cruise control. I'm wondering if I spiked something when I took off the ETA with the engine running. I talked to the tech at the dealer today and he said that maybe my home-brew scan tool will not allow a reset. He offered to hook up to his equipment and attempt a reset, but I still think my cruise control will be inop and, besides, taking it down there is like admitting defeat.

I read that there is a fuse in the diagnostic module. Could that be the problem (or maybe another fuse in one of those modules)?

Victor300E · #51 10-25-2007, 09:00 AM

I had my MAS disconnected many time with engine running or not running but I never had problem with CC doing that. If I disconnect MAF with engine running idle speed would not change but when I connect it back idle will drop to like 100rpm and then raise back to normal 550 or so.
I can't help you with your problem but I thought that I should type some of my experience with connecting and disconnecting things. Isn't one of ETA functions to work as CC actuator?

JimF · #52 10-25-2007, 10:48 AM

Quote:

Originally Posted by emerydc8

DM ECU:
DTC 4 = AIR inoperative
DTC 6 = Idls Speed control inpoerative
DTC 19 = Fuel injectors bad or self-adaptation in LH-SFI control module (N3/1) at limit
EA/CC/ISC ECU:
DTC 3 = EA/CC/ISC actuator (M16/1)
DTC 6 = Starter lock-out/backup lamp switch (S16/3)
DTC 11 = Fuel safety shut-off to LH-SFI control module

. . cleared all but the DTC 19 on DM module (as expected) and the DTC 3 on EA/CC/ISC module.

I know what's causing the DTC 19 and it's probably been there for an half decade. The only remaining code that's a problem is DTC 3 on socket 7, which (I think) is the cruise control. I'm wondering if I spiked something when I took off the ETA with the engine running.

I read that there is a fuse in the diagnostic module. Could that be the problem (or maybe another fuse in one of those modules)?

OK, good deal . . now there's a base from which you can proceed.

DM: #4: Either the AIR pump is bad or the vacuum line is broken to the AIR pump. Do you hear the AIR pump start on a cold engine??
#6: the "CC" is in the EA module but personally, I've never seen a bad EA module. That code, most likely, is caused by other problems. . .
#19: Maybe you have a bad injector or vacuum leak that will cause DTC#19. Check those areas and see what you find. If all is ok, I have a eprom that will fix that.

EA: #6: I would change the S16/3 asap! You read what caused my "ETA" problems and it was the switch. The contacts were corroded. MENU#24 at the bottom of the page.

There's fuses in the Base Module (Menu#8); none in the DM module.

emerydc8 · #53 10-25-2007, 04:17 PM

Thanks, Jim. I'll replace the fuses in the base module. You are correct about the cracked line from the air pump. I replaced the pump a few years ago and I had trouble securing the (then) rubber hose over the fitting next to the oil filter housing. I saw that the hose had come off and, when I tried to push it back on later, I ended up cracking it. That would explain that code.

Regarding the DTC 19 on socket 19, I'm pretty sure it's reached the limits of adjustment.

My transmission was just rebuilt a few months ago and I had a new neutral safety switch (S16/3) installed at that time.

So, my hope is that a fuse is the only thing keeping my cruise control from working. The other possibility is an expensive one. Your Menu #24 is really informative.

Victor, thanks for the input. My engine idle speed dropped when I disconnected the canon plug and increased when I hooked it back up.

JimF · #54 10-25-2007, 04:52 PM

Ok, on the cracked/broken line. It's a standard occurance since just 'cleaning' in that area can knock the line off. Been there, done that!

Thought that it was fate . . w/ the Neutral Safety Switch but if it's been replaced recently, it's most likely ok. There's no "inspection" since you have to drill out the rivits. . . . of course, you could open it for inspection to be sure and then use small (#3-4 screws, nuts) to button it back up?? Your call!

The fuse on the BM are easy to inspect so you can tell quickly. Even if one is blown, it would effect the complete assy, so odds are that all is ok.

When you're ready for a new eprom, let me know.

emerydc8 · #55 10-27-2007, 01:59 AM

Thanks, Jim. I'm finally ready for the EPROM. Check your e-mail on that.

I checked the fuses in the box and they're all okay. Just as a last resort, before looking at the more expensive fixes, I'm going to disconnect my battery for 15 minutes to see if that might allow me to clear the DTC 3 on socket 7. I'm not sure if the existence of the code is keeping the cruise control from working. Other than that, I guess it's either the CC amplifier or the CC module. Maybe I'll take the dealer up on the diagnostic offer. I saw the price on the CC module as the parts guy was surfing through the list and I think it was in the area of $1,400.

JimF · #56 10-27-2007, 10:53 AM

Quote:

Originally Posted by emerydc8

Thanks, Jim. I'm finally ready for the EPROM. Check your e-mail on that.

I checked the fuses in the box and they're all okay. Just as a last resort, before looking at the more expensive fixes, I'm going to disconnect my battery for 15 minutes to see if that might allow me to clear the DTC 3 on socket 7. I'm not sure if the existence of the code is keeping the cruise control from working. Other than that, I guess it's either the CC amplifier or the CC module. Maybe I'll take the dealer up on the diagnostic offer. I saw the price on the CC module as the parts guy was surfing through the list and I think it was in the area of $1,400.

Beckmann Industries checked these out on their test bench and will rebuild it for less than new. Their number can be found in MENU#24. You might want to check that out.

Also Jaytan I believe also does the same; phone number is in that menu. They can test and rebuild also.

emerydc8 · #57 10-27-2007, 06:20 PM

Thanks, Jim. I'll check out Menu #24 for the contact information on the ETA rebuilds. Maybe someone can explain this to me: My car doesn't have ASR and I've heard about some clutching unit associated with the ASR going bad. Is this the ETA, or is there an additional unit for the ASR-equipped cars?

JimF · #58 10-27-2007, 07:21 PM

Yes, there's different module for the "ABS" unit; look at MENU#2 and check carefully for the different modules for MBs w/ ASR.

Look at "ECU position in the F23 Module Box" . . . slots 4 + 5

emerydc8 · #59 10-28-2007, 04:55 AM

Thanks, Jim.

Well, I guess it's my turn in the barrel on the ETA. I just figured out what the problem is. 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.

Anyway, after turning the key on (engine off), when I moved the wire that runs from the canon plug to the ETA, I noticed that the buzzing in the ETA stopped. I couldn't get the noise to return no matter how much I moved the wire.

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. 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)

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.

What I found interesting about the ETA is that, even with the ETA apparently not working, the car still runs okay--other than no cruise control and a lower idle speed.

myarmar · #60 10-28-2007, 09:38 AM

This is MAF connector, not ETA