Tn-signal at Engine control module - PeachParts Mercedes-Benz Forum

Pete Geither · #1 05-20-2007, 03:39 PM

Have been trying to figure out the surging problem on the 320 for awhile now and finally built the code reader and found code 11 showing up. Tn-signal at ECM. OK,,, what is that and is it a repair or replace. Harness has not been replaced AFAIK.

Arthur Dalton · #2 05-20-2007, 04:43 PM

Tn sig is not gotten with the code reader tool ..It is an emmisions DM code and gotten w/built-in LED/SW.

Where did you get the code from???

Pete Geither · #3 05-20-2007, 05:24 PM

Got it with the code reader Arthur. No CE light has been on. Got eleven flashes on the Code Reader LED.

Arthur Dalton · #4 05-20-2007, 05:35 PM

Quote:

Originally Posted by Pete Geither

Got it with the code reader Arthur. No CE light has been on. Got eleven flashes on the Code Reader LED.

Oh..
Well , I guess what I mean is ...if you used the built-in led/sw , you will get the codes from the DM..which would be a TN signal for a code 11.
But......
My question stems from the fact that you said you has built the code reader tool and used that..if that is the case , the tool is to go to the other modules on the Box [ pins 8 or 14] and if that is what you have done , then a code 11 is not a TN sig code.
Just making sure you realize this so you are not going in the wrong direction.

Here are the codes that correspond to both the Tool you made and the built-in led/sw ones ..as you can see , that is why I ask where you got that code from..

http://www.peachparts.com/shopforum/showthread.php?t=107630

If you are already aware of this , please just disregard my post.

Pete Geither · #5 05-20-2007, 05:42 PM

OK Arthur,, this is what I did,,,, got 11 flashes off the reader on pin 14, and just went out and checked pin 8 and got 13 flashes. The reader sure is pretty anyhow,,, the flashing lights impressed the crap out of my wife.

Arthur Dalton · #6 05-20-2007, 05:57 PM

Quote:

Originally Posted by Pete Geither

OK Arthur,, this is what I did,,,, got 11 flashes off the reader on pin 14, and just went out and checked pin 8 and got 13 flashes. The reader sure is pretty anyhow,,, the flashing lights impressed the crap out of my wife.

Yeah . Flashing Lights always work...I always wanted to build a whole wall of them that did nothing but amaze the observer.. a few wierd audios thrown in there too...

..anyway, as you can see , the tn sig would be a code from the DM module and not related to your problem Those DM codes are gotten from the built-in led [ N59 Emmissioms Module] and that is what brought my attention to your code/module error.

A code 13 on the HFM [ ecu] module means the 02 sensor is running at an upper rich limit, so I would look around for a vac leak ..might want to start at the front plastic vac line running across the front of engine. under the cover..they are notorious on 104s for breaking due to heat fatique.
The othe code from 14 means you have a CTP [ closed throttle position]sw that is not closing all the time ..I would look at the adjustment for this [ you want a little slack in the cable at idle] and I would lube the cable ...this is another common code/problem on 104 HFM/SFI systems ..

I would also go use the built-in reader just to see if any of that info has gotten back to the DM..it can have pending codes in there and not trigger a CE.

Pete Geither · #7 05-20-2007, 06:46 PM

Thank you Arthur,,,, will check the areas you mentioned right after din-din.

Pete Geither · #8 05-21-2007, 07:47 AM

I repaired the plastic vaccum line in the front of the engine a couple of weeks ago and rechecked it to make sure there are no leaks,,, it seems good. There seems to be enough slack on the throttle cable also. A couple of weeks ago I replaced the E-brake cable which required a lot of tearing apart of the console and lower dash,,, are there any vaccum lines inside the car I could have disturbed ? I am going to try to get the car on one of our lifts today and check under the car for lines loose or missing also. Dang thing is still surging pretty bad. Thanks for the help Arthur.

Pete Geither · #9 05-22-2007, 07:58 PM

Have examined every vaccum line I can imagine and nothing to be found. I was thinking I could tackle this deal, but it's looking like it's time for the pros $$$$$$.

Arthur Dalton · #10 05-22-2007, 08:18 PM

Take the vac hose off the fuel pressure regulator and see if there is any gas leaking out of the port..should be NONE.
If there is any evidence of gas in that line, change the regulator...
You also want to check codes in the DM. That is w/the built-in led/sw combo.

Pete Geither · #11 05-23-2007, 05:57 AM

Sorry to be a pain Arthur,,, but where is the Fuel Pressure regulator ?

Arthur Dalton · #12 05-23-2007, 10:02 AM

On the front of the fuel rail..round, saucer looking device ..thermostat area , a little back and higher...silver metal color

Pete Geither · #13 05-23-2007, 10:58 AM

Quote:

Originally Posted by Arthur Dalton

On the front of the fuel rail..round, saucer looking device ..thermostat area , a little back and higher...silver metal color

Thanks Arthur,,,, Now I know

Arthur Dalton · #14 05-23-2007, 11:06 AM

OK

Also, when you check it, hold your finger over that vac line and make sure there is vac there when running.
The regulator had a diaphragm in it and what happens is the dia. leaks and then the gas get sucked into the engine through that vac line, causing your erratic rpm behavior..[ unmetered a/f mixture.] fairly common and easy diyer check/fix.

david s poole · #15 05-23-2007, 11:24 AM

pete,been reading your thread and had the same prob with customer car several months ago.it wound up being a separate computer/relay on the floor in front of pass feet.i had assumed that main f.i. computer operated the idle but not the case.i went to salvage yard and found the part and fixed the problem.[this client had gone to expense of changing out the electronic accelerator with no effect]