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?

__________________
Zafar
94 E320 58000 Miles

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.

__________________
Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

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.

__________________
1992 Mercedes-Benz 400E
2002 Mercedes-Benz ML500

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.

__________________
Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

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?