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2000 Mercedes ML-320
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Discussion Starter #1
This is another story/description of exactly the same issue I have with my 2000 ML320.....

It's throwing P0720 & P0500.... MY CAR IS THROWING CODES PO600-1605-and-1491 as well.

It's not the conductor plate, wheel sensors, fluid level or anything obvious.
Vehicle goes into limp mode immediately (at start up) when ambient temperature is roughly 60F or below.
I have determined that engine compartment temperature is what matters.
I've implemented an unorthodox test when car was stone cold, with ambient temp between 55F to 60F.
I used a bullet kerosene heater, aimed at the engine compartment for 15 min or so. Got in the car and problem was gone.
This isolates the thermal increase to the engine compartment, as I am sure the internal temps of engine and or trans would remain at ambient temps, in-spite of increased engine compartment temps within a 15 minute duration.
No operating temperatures would occur without engine being fired up.
Without the Kerosene heater test, the same resolve of said issue will occur naturally and somewhat quickly in 60F temps and above (even before reaching operating temp) and diapering entirely in summer weather.
However, in colder weather (say 40F to 30F) said issue will resolve, only after a prolonged period; until totally reaching operating temp.
When I say (limp mode) I mean that the car throws dash lights: BAS/ESP, ETS, ABS and vehicle will not shift out of first gear. -

Put that one in your pipe and smoke it. Please let me know what you come up with.
 

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Premium Member
Current (2002 ml320, 2002 ml500, 2005 ml500 sport 2006 bmw 525xi)
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If increasing temperature makes everything work, then I would be looking at wiring and connections. Metal expands and contracts with heat. Did you do any work on the car prior to this problem that could have moved or pulled any wires, harness or sensors?

Start with the wheel speed sensors and any connectors that would be part of the system warning the computer to place the SUV in limp mode. Or, take a heat gun to each of the sensors and see if you can isolate any wire or harness that is a part of this system. Or get an scanner that can read ETC, Body Codes, etc. you need to find out if a sensor is failing when temperature changes. This is easier then tracing every wire in the car. Let us know what your results are.
 

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2000 Mercedes ML-320
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58 Posts
Discussion Starter #3
Ok Thanks,
I have checked the 4 sensors for continuity they all seem to be around 1060, I checked all the connections while doing that as well.
I just ordered a conductor plate kit as I found that the 13 pin connector was very oily and from what people are saying online It seems that once the conductor plate Is worn out it effects the 13 pin connector potentially casuing limp mode. Any idea/ideas where I could start and maybe a few places to look?
Sensors to check?
There seem to be an awful lot of them and Im really struggling with mooving foward on this project?
Thanks again so much for your time,
Very appreciative!!!!
 

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Premium Member
Current (2002 ml320, 2002 ml500, 2005 ml500 sport 2006 bmw 525xi)
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The conductor plate bolts to the valve body and holds the solenoids that control the shifting, and contains other sensors as well. The failure of the conductor plate is usually in the copper connections on the plate that the solenoids make contact with, or failure of one or more of the sensors on the plate itself.

41LXI7UtNnL._AC_SR160,160_.jpg



The fluid you have in the connector is usually not a failure of the conductor plate. It is a failure of the o-rings on 13 pin transmission coupler. These o-ring seals around the connector on the plate and the transmission itself. When the 0-rings fail, fluid flows into the 13 pin connector and then works it's way up the wiring loom into the control module located in the center console. Just like a wick, capillary action pulls fluid into the control unit which can destroy it.

61b8AA8O+aL._AC_SL1000_.jpg



So, what are your thoughts?

Have you abandoned your temperature theory?

I was also thinking about other reasons why you would get error codes that would go away after warm up. How charged is the battery? Can you charge this overnight? Mercedes are very sensitive to voltages. My son's car (ML320) had warning lights go off and into limp mode after he left the lights on overnight. So running the car for awhile would bring up battery voltage as well as increasing the temperature in the engine compartment could effect battery voltage if the battery was weak.
 

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Premium Member
Current (2002 ml320, 2002 ml500, 2005 ml500 sport 2006 bmw 525xi)
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So, check the wiring after the 13 pin connection headed into the car. Are the wires full of transmission oil? If so, trace up to the ETC and take a look inside. If not, breathe a sigh of relief.

Here's a link to all the details of the 13-pin connector

 

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2000 Mercedes ML-320
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58 Posts
Discussion Starter #6
Very interesting I will charge the battery today, I checked the voltage yesterday and it was 12.69 with engine off, and 14.3 with engine on... But will check charge and check, so far I have read a few descriptions of Conductor Plate's going bad and it seems relatively similar... I guess I wont know until I replace it. I will also check 13 pin connector wires today as well as ETC unit. Will keep you posted!! Thanks again.. all very helpful info
 

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W163 and General M Gremlin
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A general conductor plate DIY for 722.6 transmissions - pretty much the same procedure over all the models that share the same one.
 

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2000 Mercedes ML-320
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58 Posts
Discussion Starter #9
Checked the battery today was all ok,
I also did something stupid!! ..
I Tried to start My ML320 with out the Transmission Control Module accidentally. Also forgot to unplug battery when I put it back in...🤭very silly!!

I plugged the module back in and
Now It Wont Fire!!, engine just turns over???
Do I have to RESET codes for the module/modules?
What can I do?

I'm trying to decide which scanner is best!!

Autel MD802
icarsoft????
FOXWELL NT530 or any other suggestions?

I'm hoping to find one that reads and delets all codes and preferably live codes..

Any Suggestions which would be good for my car
2000 ML320 w163?

Thanks a MiLLION
 

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W163 and General M Gremlin
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3,699 Posts
Checked the battery today was all ok,
I also did something stupid!! ..
I Tried to start My ML320 with out the Transmission Control Module accidentally. Also forgot to unplug battery when I put it back in...🤭very silly!!

I plugged the module back in and
Now It Wont Fire!!, engine just turns over???
Do I have to RESET codes for the module/modules?
What can I do?

I'm trying to decide which scanner is best!!

Autel MD802
icarsoft????
FOXWELL NT530 or any other suggestions?

I'm hoping to find one that reads and delets all codes and preferably live codes..

Any Suggestions which would be good for my car
2000 ML320 w163?

Thanks a MiLLION
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Also, there is no need to double post (on a separate thread) the same topic.
 

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2000 Mercedes ML-320
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Discussion Starter #11 (Edited)
Sorry, can someone tell me wether its worth getting one one of these scanners or is my car dead now because I have ruined the module components? cant start it?? Dont want to pay for a tool if it doesnt do anything!! Thanks
 

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W163 W202 W203 W246 MB100D
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68 Posts
hi mate, did you end up buying a scanner? or had any luck reviving your ML (while in lockdown) ?
not sure if the car is dead but definitely need a scanner with mercs, otherwise its like working on a computer without a display monitor.
I went with icarsoft and is sufficient for my ML, but foxwell/autel seems to be able to read more data etc.
good luck.
 

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2000 Mercedes ML-320
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58 Posts
Discussion Starter #13
hi mate, did you end up buying a scanner? or had any luck reviving your ML (while in lockdown) ?
not sure if the car is dead but definitely need a scanner with mercs, otherwise its like working on a computer without a display monitor.
I went with icarsoft and is sufficient for my ML, but foxwell/autel seems to be able to read more data etc.
good luck.
Legend!! Thanks mate I just got the Autel MD802. Today I changer the Conductor Plate and I noticed the O-rings on the trans solenoids are fairly worn out, going to replace them and put it all back.. Hopefully I will be able to clear the codes with the Autel.
Will keep ya updated.
 

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2000 Mercedes ML-320
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Discussion Starter #14
Oh no!!!!! This is what my Autel has shown me....Anyone out there able to guide me a little here as I am very confused as to what to do next..? Thx
2643843
 

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2000 Mercedes ML-320
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Discussion Starter #17
I went into each module, Transmission, Body .. etc and went through every fault.
I deleted the codes individually last night and the same thing happened again this morning.. will try doing it again and see if it makes a difference tomorrow morning.. Did you get the codes? I tried uploading a pic..
 

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2000 Mercedes ML-320
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Discussion Starter #18
You have changed conductor plate based on what? Particular fault or gut feeling?
Speed Sensor Fault and the trans was showing symptoms of a bad conductor plate.. It definently made a difference.. feels smoother to change gear and less clunky.
 

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Discussion Starter #20
Ok now there are no faults... went for a drive for 30mins.. checked again still no faults or lights on dash. Will check again tomorrow morning
 
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