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:



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.

Attached Thumbnails

 

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.