95 E320 Fault Codes 2, 5, 8, & 17
 

My CE light came on and LED ck indicates codes 2, 5, 8 and 17.

2 = oxy sensor inoperative
5 = EGR inoperative
8 = coolant temp sensor open or short circuit
17 = CAN data exchange-malfunction betw. control units

After a search of forum articles I plan to: ck vac lines, ck EGR valve w. hand vac pump, ck o2 sensor w. DVM as prescribed by A. Dalton.

I am wondering however if anyone has encountered this string of fault codes and can steer me to the likely problem source. All input is appreciated.

Check Wiring harness
Check HFM-ECM and the various other modules for codes using the led tool.

Any adverse effect on vehicle operation?

My God Jack, you got hit all at once. You have cleared the codes and checked to see if they return right?

The wiring harness was replaced about one year ago by the dealership. The engine currently runs fine w. the CE light on.

I have not cleared the codes to see if they all return. Good idea and I will do so.

Clear the codes and then run it for a few days before you check them again. Please post your findings and then we'll go from there. To me it sounds like someone was doing some troubleshooting while the engine was running (removing and installing connectors and vacuum lines perhaps). Sound possible?

Good luck

Jack
I sent the tool construction/ instructions to you a couple of days ago as requested....
Did you get it??
I did not recieve a reply

Anyway,as said, make tool and get codes from pins 8 and 16..[along with what you have form DM]
That will get you a little more info .

Dale, I will clear codes and see what happens. BTW no one has tampered with the engine.

Arthur, thank you for the LED instructions. They are straight forward and I will let you know the results once I make the tool. Thanks to all for your help.

It's not that someone has tampered with the engine.

Some of the codes could be old codes that have been stored (and not cleared) from the computer from when the wiring harness was replaced.

That makes more sense Paul, especially since he said his engine runs fine. That's why I found it strange to have so many codes and no engine running complaints.

My car has codes 4,5, and 17 appearing but runs fine. I will eventually get around to it but I figure that its not causing any trouble so there must be one small problem affecting these systems.

Paul and Dale, the CE light never came on when I had wiring harness problems. At that time I only experienced significant engine hesitation during acceleration and since the vehicle was still under a 100K warranty immediately took it to MB for a new harness and plugs. It has run fine since then.

I made the LED tool last nite and will run codes and report back.

Heck, my CE light didn't come on when my wiring harness was acting up, either.

The CE light didn't come on when my throttle actutor went out, too.

Update. I cleared codes 2,5,8 &17 from the emissions module (LED/switch). However I could never get the two flashes confirming that all was clear. When the switch was held for the necessary 3-4 seconds and released the LED remained blank. The CE light remained on when starting the engine.

With the LED tool I went ahead and checked pins.

Pin 8 read 1 (clear).

Pin 14 read 5. I cleared.

Pin 10 would not give any signal not even 1.

Pin 7 read 1 (clear)

Pin 6 read code 8 and I am unable to clear it.

Upon restarting engine the CE light is off. I have not driven enough to see if it will come back on.

Why can't I get the emissions module to give a clear signal and what is the diagnosis for pins 14 and 6?

[QUOTE]Originally posted by Jack500
[B]Update. I cleared codes 2,5,8 &17 from the emissions module (LED/switch). However I could never get the two flashes confirming that all was clear. When the switch was held for the necessary 3-4 seconds and released the LED remained blank. The CE light remained on when starting the engine.

DM will not give a OK flash [ single, NOT double] until the DM has checked ALL systems [ many drive cycles]

With the LED tool I went ahead and checked pins.

Pin 8 read 1 (clear).
Good

Pin 14 read 5. I cleared.
Stop lamp switch [ wait to see if re-appears]

Pin 10 would not give any signal not even 1.
nothing there

Pin 7 read 1 (clear)

Pin 6 read code 8 and I am unable to clear it.
SRS system .that should be a digital sig from 94/95

Upon restarting engine the CE light is off. I have not driven enough to see if it will come back on.

Fine , watch it for new codes he CE will not go OUT after code retrieval until you turn key off for 10 sec and then restart car]

Arthur thanks for the input. I'll drive the car for a week and then re-check codes assuming CE light comes back on.

In doing the code checks I did notice that about 30 seconds after turning the ignition on I would hear a click and then a constant humming sound coming from somewhere directly under the intake manifold. I cound not pinpoint the exact location. Is this normal?

After 8 days of daily driving the CE light has come back on. I checked the DM and have a code 2.

Pin 8 shows code 9.
Pin 14 shows code 1 (clear).

The archives indicate the DM code 2 refers to a bad O2 sensor. Is this correct? What is code 9 for pin 8 (HFM)?

I have the two disc CD manual for the 124 but could only locate one page that describes the 16 pins found on the diagnostic connector. If the codes for the various pins are somewhere on the CD can someone direct me to them. I have looked and looked.

HFM module code 9 is implausable 02 sens signal..
You can easily check the sig/sensor w/dmm on that car by looking for a rich voltage when disconnecting the Fuel pressure regulator vac line and a lean reading by inducing a vac leak at the SOV vac line..
Looks like 02 sens time , but I would verify w/testing.. Connector is under rug-pass side

CD is Useless for codes
All-Data is great...

Follow up
 

I resolved my problems by installing a new O2 sensor. Used the Bosch 13275 4-wire that others on this board have mentioned. All codes cleared and have remained absent for many months.

CE light has however now come back. DM shows a code 5 (EGR). All clear at pin 8. I checked the vacuum line at front of engine and the EGR valve. Both OK. Ran a speedometer cable down the tube from EGR valve to air intake as prescribed in Steve B's article. Cable would not run through completely to end (I ran it in about 36 inches) so I imagine I have a carbon deposit build up at air intake. I plan to detach tubing and check out. Will report back.

Disconnected the EGR tube at air intake. At least on the 1995 E320, this first required removing the forward two 10MM bolts holding the accelerator cable harness. The third bolt at the rear of the harness is difficult to access but does not need to be removed since the harness will pivot at this point providing adequate room to reach the EGR tube. The two 10mm bolts holding the tube come out easily. There is a gasket here but mine remained firmly attached to the air intake and so I left it alone since I did not have a new one.

However, the EGR tube itself would not come free. I had to detach tube at EGR valve and also disconnect tube holding bracket located at oil filter. Seems the 1995 model uses a tube that has an extended insert sleeve (about 1 inch long) that slides into the air intake assembly. My tube was not flush with the air assembly as shown in Steve Brotherton's article. Anyway, at this point I could blindly pick at the carbon build up in the tube using a short piece of clothes hanger wire. This was enough to then get the speedo cable freely through the tubing starting at the EGR valve end. Did a flush with Gunk and then brake cleaner. Wished I had compressed air available but still feel I got it very clean.

BTW I had first made a quick attempt to remove the tube from the engine compartment for cleaning since it was entirely free. However, it does not appear that this is something that is easy to do without removing other components. I was just happy to have gotten this far and left it in place for cleaning. A 1/4 " ratchet set with various extensions works good in the tight places but 3/8" will also work.

Hope I do not see a Code 5 pop up anytime soon and that these instructions will help others.