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2004 ml500
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Discussion Starter · #1 ·
if i replace the ecu in my car with one from a junkyard does it have to be coded/reprogrammed?
 

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SEC 600 V12 2dr COUPE (RHD) One of the chosen few.
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MB have adopted a CAN recognition system with all their modules.. It would need to have the CAN code cleared before it will work with your system..So if you cant get the code cleared .. dont buy it.. You might try a different chip in your ECU instead
 

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Discussion Starter · #5 ·
which chip inside of the ecu would i replace i already own a 2nd ecu from the junkyard its known to be working but once i put that in the car wont start. I have a code reader and im not getting any codes now with the new ecu
 

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Ok so if your first ECU works on the car it will be TWINED to that CAN Buss module This has a complex two way conversation to establish that the thing it is talking to is the correct part..If it dosn't get the right signals it wont play.. The second ECU will be twined to the can buss on the donor car..You need to have the can buss register in the ECU module flushed or it wont work..

Replacement chips .. Hi-Performance..on ebay.. ask before you buy..
 

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SL55, 300SE, GL450, Daytona 955i
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just out of curiosity, why did you replace the ECU?
 

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2004 ml500
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Discussion Starter · #8 ·
was getting misfire codes without anything causing them. wiring is good new coils new maf new iat sensor new injectors great fuel pressure. No vaccum leaks. Theres nothing to cause the misfires
 

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Did the CAN report the ECU being the part to blame?

Check your compnents one by one again... one of them is bad.
 

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2004 ml500
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Discussion Starter · #10 ·
i dont have any diagnostic software to read the CAN. What other components would cause random misfires on only one side of the engine? I thought i checked everything thats why i changed the ecu. But if you think another component is causing this i will return the ecu today and put hte old one back in.
 

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crank and camshaft sensors.. engine temp sensors.. MAP sensor..lamda sensors.. to name but a few. you need to find a way to pull the codes.. then we can help you.. where are you located?
 

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2004 ml500
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Discussion Starter · #12 ·
new york usa. i have a new cam sensor and a new crank sensor. Temp and map sensors are both good tested. I have no o2 sensors on that side of the vehicle because of the last misfires it fried the catalytic converter and blocked up the whole exhaust on that side of the motor so i didnt want to risk putting my new exhaust on there and have the misfires kill that one too. would a o2 sensor really cause these misfires?
 

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well.. the mixture control is governed in part by the O2 sensor..it adjusts rich and lean settings and on my twelve the left O2 unit tells the right bank what mixture to set and the rightO2 unit tells the left.. so you have a huge imbalance in your system take them both out... and go back to basics..plugs leads connectors etc.. someone on here or near you must have a code reader.. I can only say that you need to try and pull some codes so we can help ..
 

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Discussion Starter · #14 ·
i have a code for o2 sensor bank one sensor one but i thought bank one was for the passenger side o2 sensor the first one in the pipe. That one isnt connected because of what i explained earlier. so if you are correct right goes to left and left goes to right then my driver side should be misfiring not the passenger.
 

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1998 140.070 CL500, 1966 406.121 U65
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well.. the mixture control is governed in part by the O2 sensor..it adjusts rich and lean settings and on my twelve the left O2 unit tells the right bank what mixture to set and the rightO2 unit tells the left..
I think you are confused about your air intake, MAF and intake plenum being crossed over
the heads of the engine. Certainly, the left O2, gives feedback of the mixture for
the left bank, right O2 sensor for the right bank. Last time I looked, the exhausts
do not cross each other under the car? Right O2 can never "see" exhaust from the left
side. Right?

br,
syljua
 

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As I said in my 12 the left tells the right and the right tells the left.. I think it must be the same for your 8..however .. you will now have hit the extreme mixture setting on one side only way to sort it is pull the codes and list them here..then we have info..not speculation..
 

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1998 140.070 CL500, 1966 406.121 U65
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As I said in my 12 the left tells the right and the right tells the left.. I think it must be the same for your 8..however .. you will now have hit the extreme mixture setting on one side only way to sort it is pull the codes and list them here..then we have info..not speculation..
Hmm, in previous posts you write;
the left O2 unit tells the right bank what mixture to set and the rightO2 unit tells the left..
The right hand O2 will adjust the mixture on the right hand combustion (bank),
and the left hand O2 will adjust the mixture on the left hand. Crisscrossing
that, will make no sense...

Now, and this is perhaps what you mean, after each side has dealt with its side,
in the M120, they (the ECUs) then tell each other their value, to compare and rise issues
if somethings wrong.

BTW, Bernard in the S-klasse-club.de has posted some new nice images of
his new build 7.4 M120;
http://community.forenshop.net/forums/index.php?mforum=W140&showtopic=5883&st=0

br,
syljua
 

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2004 ml500
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Discussion Starter · #18 ·
got freeze data for the time of fault

DTC that caused freeze frame
p0300

Engine RPM
725rpm

Load Value
28.6%

MAP Sensor
52 KPA

Coolant Temp
122 ºF

Short Term Fuel Trim1
0.0%

Long Term Fuel Trim1
0.0%

Short Term Fuel Trim2
25.0%

Long Term Fuel Trim2
0.0%

Short Term Fuel Trim3
-100.6%

Long Term Fuel Trim3
-100.6%

Long Term Fuel Trim4
-100.6%

Short Term Fuel Trim4
-100.6%

Vehicle Speed
0mph

Fuel system 1
OPEN2

Fuel System 2
CLSD1

at this time i had gotten these codes P0304 P0303 P0300 P0130 P0135
 

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po300-303 304 = misfire cyl 3 and 4.. po130 o2 sensor circuit malfunction bank1 sensor 1--po 135 o2 sensor heater circuit malfunction bank 1 sensor 1 po300 random misfire

looks like your fuel system has hit the buffers on one side like i said previous..L controls R and R controls L take lead out of maff and unplug the o2 sensors.. then fire up and listen see if it smooths out..
 

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1998 140.070 CL500, 1966 406.121 U65
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looks like your fuel system has hit the buffers on one side like i said previous..L controls R and R controls L take lead out of maff and unplug the o2 sensors.. then fire up and listen see if it smooths out..
Ok, I think we have to get things strait here. This fault is for a car with M119, single MAF,
2 banks with one of the banks missing the O2 sensor.

I think the readings tell;
Bank 1, is running in a open loop mode. It (the ECU, only one on the M119) has done this,
because it knows that is cannot preheat the O2 sensor, P0135 O2 sensor heater circuit malfunction bank 1 sensor 1. A O2 sensor will not work with temp under 250C, and since it thinks that it cannot preheat it, it will disable the closed loop, and use open loop mode for that bank. Since, in this car, the O2 sensor is not even there, this is a correct decision.

The open loop mode, will then adjust the mixture on bases of intake air volume, and manifold pressure/ butterfly spindle position. Looking at trim values for that open loop bank, will then give no meaning, because trim is only being used in closed loop (like bank 2 is).

Removing the remaining O2 connector, will only bring bank 2 to open loop mode.
(and once more, bank 1 mixture is regulated by O2 bank 1 sensor 1, bank 2 by O2 bank 2 sensor 1!!)

If, for some reason, the MAF gives wrong readings, the open loop equation will
fail, and car run badly. Removing the MAF input, will then remove some of
the inputs in that open loop equation, and perhaps improve things, but at
the same time, it will then default to an even more non-optimal state.
What you are then doing, is replacing a wrong input parameter with a fixed
knowledge based one (that the air mass coming in, is a function of the other parameters
left in the equation).

atv087, I think that you will have to introduce the O2 sensor on bank 1 again.
That, in combination with checking the MAF. ECU rarely goes wrong by
itself, and if it would, a lot more would be wrong, and from the state
of your car, it is telling you the correct things.

I think that you are having problems with you spark plugs. A faulty spark plug, would
cause that previous miss fire, and build up fuel excess that would
destroy the cat (like it did). A faulty coil pack on the other hand, would be detected and
turn off the injector for that cylinder, and keep going (yes, I`ve been there)

br,
syljua
 
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