W124, M104 DM Code 6 and 17; need help
 

I have an W124 with an M104 and it threw DM codes 6 and 17.
I have looked those codes up but am unsure what other diagnostics I can do?
Or what parts I might throw at it?
Does a bad O2 sensor have anything to do with it?

Posting what the code description would be helpful.

DM Code 6: Idle speed control inoperative
DM Code 17: Data exchange malfunction between individual control modules.


I will be checking code from pin 8 and 14 the next chance I get to work on the car.

Update:
I checked pin 8 and pin 14.
Pin 8 code: 8
Pin 14: codes 2, 5, 7 and 11
I wonder what triggered the CEL and what the culprit is?

Update:
I checked pin 8 and pin 14.
Pin 8 code: 8
Pin 14: codes 2, 5, 7 and 11
I noticed that the cruise control isn't working either.
I wonder what triggered the CEL and what the culprit is?

A bad O2 sensor would not cause this issue.

The cruise might be dropping out due to idle speed control issues. This car should have a throttle control computer correct? I'd start there.

I started working on my ETA throttle so I started taking things apart.
I found that the throttle return spring was broken and I also found a disconnect vacuum line near the back of the intake manifold.


However, I can't see to find the darn plastic vacuum line that is supposed to be connected via a rubber vacuum hose.


The small black rubber hose was gummy and broke apart in my hands.
There are supposed to be two vacuum lines connect beneath the back of the intake manifold. The one that is still there has a clearish plastic vacuum line and the other is missing.


Does any one know if the on of the vacuum nipples is just supposed to be capped off with a rubber boot? Does any one have a vacuum diagram of the area in question?


Thanks.

Try this vacuum diagram:

https://uploads.tapatalk-cdn.com/201...50afe00eb1.gif

You should also see one on the passenger side front radiator mount.

On my E320, there's only one vacuum nipple on the back of the intake manifold. It goes to the 3 prong check valve behind the brake booster.


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Thanks for the diagram. I am thinking of the nipples on the lower intake manifold. The nipple I am talking about is the one in the pick circled in red.

W124, M104 DM Code 6 and 17; need help
 

That goes to the diagnostic module pressure sensor (B5/2 in the diagram above). That device tells the ECM the intake vacuum or pressure in order to set lambda at idle in case your MAF fails. The sensor in my car is next to the ABS and Purge Valve (MOT) and is bolted to the driver side front wheel well. You should connect it with a vacuum hose. That might be the reason you got code 17.


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The nipple next to the one circled in red is connected to the B5/2.
So B5/2 is connected.
I am trying to figure out where the circled red nipple goes to. The diagram doesn't show. I have the M104.99x with no EZL.

Here is the pic.

I was hoping to find a stranded plastic tube somewhere but don't know where to retrieve it if I am not sure what connects to that nipple.
I appreciate your help.
Thanks

It may go to the HVAC system, the emission vac diagram won't show that.

It may also have had a rubber cap since engines are generally built to fit a few different cars.

I also own a 1995 E320 coupe. I checked that area on it but it does not have two nipples on the lower intake manifold. Same engine, harness, etc, but does not have that nipple on it. I am thinking that nipple has a rubber cap on it. Maybe the lower intake on my 1993 in a left over part from 1992 cars which maybe utilized that nipple.

W124, M104 DM Code 6 and 17; need help
 

Here are some pics of my E320's intake manifold vacuum connectors showing the circled nipple from your photo as the one going to the DM pressure sensor (B5/2) shown in pic 2.

The other nipple closer to the cylinder head has a Y connector going to both the fuel pressure regulator (40), and air injector (Y32) & EGR valve (Y27).

It's exactly how the diagram I posted above shows.

https://uploads.tapatalk-cdn.com/201...23615330fe.jpg

https://uploads.tapatalk-cdn.com/201...41d4a22c4d.jpg

https://uploads.tapatalk-cdn.com/201...0a88fdee3e.jpg


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I apologize. I circled the wrong area. The area I circled is where my lower intake has a nipple. So I am almost positive my 1993 has a 92' lower intake which has that extra nipple. 93'. Now I am almost certain that that nipple is probably capped with a rubbed cap.

W124, M104 DM Code 6 and 17; need help
 

No problem. On my E320, that nipple connects to the 3 prong vacuum supply connector behind the brake booster (135). I should know since I just replaced the rubber boot connecting a white vacuum hose to that nipple a few weeks ago. See vacuum line at bottom of pic below.

https://uploads.tapatalk-cdn.com/201...30ba5fae16.jpg

The right-most of those 3 prongs connects to the transmission upshift retard switchover valve that has a green hose going to the transmission retard switch. It retards 2nd to 3rd gear upshifts at coolant temps below 50 C.

The other two lines go to the vacuum reservoir for door/boot/gas locks and HVAC flaps.

https://uploads.tapatalk-cdn.com/201...5b77d8803c.jpg


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Sorry for lengthy explanation above. I just looked at the circled area again and my intake manifold does not have that nipple there as well.


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I took the ETA out and out in a new ETA gasket.
I drove the car for 30-40 miles and the CEL triggered.
The DM codes that came up were 4,5, and 6.
I checked pin 8 and got a code 8.
I checked pin 14 and got a code 2.
These are the codes that returned within 30-40 miles..
I don't remember having DM codes 4 and five before. I had DM 6 and 17 in the past.
maybe 4 and five came after I possibly bumped a vacuum line. I will check hoses again.

Do any of the codes above indicate a clogged egr tube?

I]other issues I am having is that my cruise control is not working either.

Any chance that these code are related to a clogged egr tube?
In addition, my cruise control doesn't work any more.
Car doesn't run too badly, but the idle drops a little too much when the AC is turned on.

just a thought, too..is the ETA wiring issue which was similar to the engine wiring harness. My E320 required a new ETA for the ASR type system in 2005 due to the eco-junk wiring. Somebody said if its not one thing, its two. Hope you dont have bad ETA wiring. good information on this around the vacuum system! Thanks for details!

PS, the note about cruise control suggests the ETA wiring is faulty..But these other guys are way ahead of me here! I had a 94 coupe with the M104 and the cruise would drop if I hit a bump. clearly an insulation degradation issue.

Solved.
Thanks too all who chimed in on this thread.
Mercron, great pics and diagram.
I appreciate Arthur Daltons help as well.
Puzzler, it was the ETA.


I suspected it too, but had wishful thinking that it wasn't the ETA.
Put in a used but in working ETA and everything is working really well now.
My other codes related to vacuum lines were resolved-I had accidentally knocked of a line that didn't have much slack on it. I gave it more slack and hooked it back up.

If you look close, notice that all of the wires, except the black ones, have deteriorated insulation ! We all know about the eco junk wiring etc., but wow !

W124, M104 DM Code 6 and 17; need help
 

Codes 4 for the air injection and 5 for the EGR faults could be related if you knocked off the vacuum hose going to the two switchover valves they're connected to.

Glad you solved it with the ETA wiring.




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Stevester 500E, thanks for sharing! Good to know. Im getting there and glad to know you solved this. I hit the jackpot with my $600. E320 finding it had a 2005 ETA installed by the dealer. I tore it all apart trying to diagnose a crazy fuel pump failure which was intermittent. I suspected the E-modules, the ETA and everything but fuel pumps which were both previously working fine, then BOTH failed within a week! Your car must be an ASR model. My transmission is trying to fail and here I have a bullet proof engine and $1000 worth of new parts and still looking at another $2000 repair to do the transmission. But hey, my self-leveling suspension works great.. Hope you found the ETA for a reasonable price..

Maybe you can find a deal on a good used transmission. Sometimes you can find a car being parted out with a fairly recent transmission rebuild.

Ive been looking for a trans and meanwhile it has fairly good function after being treated with blue devil stop leak which revived the reverse gear seals. Thanks again for all the details!

Puzzler, what's the color of the transmission fluid? I'd change the fluid to Dexron 2 if it's old already.


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Thanks MERCRON, the fluid is okay and Ive changed it repeatedly to revive the old trans which has/had a bad reverse gear. Forward gears are fine. I used castrol for high mileage which helped, then flushed with the tranex product which brought back reverse for a while but then it dissapeared again. I replaced the fluid again and added blue devil stop leak with the Pentosin trans fluid that I put in this time, with new filter too. Then I overfilled a bit and reverse was good but the forward gears began slipping, NO FOURTH at all! So I drained out all the fluid and put back only enough to reach the mark and it was good again. It ran for about six months this way but I began backing uphill into a work space and this took its toll and lost reverse again. So I treated again with blue devil and now reverse is back and I do not back up hill ever! I head in up hill and then let it back out downhill only! It will also back up on the level but sometimes chatters viciously..And a rebuild is beyond the value of the car now since I had a smash up in the ice and snow this winter. Its put together passably but will never be truly right again. So yeah, Ive flushed the fluid and used Lucas
stop slip and also the blue devil with BD being the one that really makes a difference. 215K on the trans if its original.

Normally when reverse fails, it fails quickly and its permanent. It sounds like your transmission might just be slipping due to wrong fluid. Have you tried just plain Valvoline Dexron 2 dino? Are you also draining the torque converter? These transmissions also do not like being overfilled. Measure when engine and transmission has been running at least 20 min at normal operating temperature.

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