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00' ML55 AMG, 98' E430, 95' S320
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91 Posts
Discussion Starter #1
My symptoms are fan runs ONLY up to 20-25%, NO higher. It comes on under two conditions (only). First one is when the A/C compressor is ON, it will cycle on and off at a fixed interval, and run at the same 25% each time, no variance. Second is when the temp gets to about 100C (or so) and runs for a short time @ 25% again. No faster.

I connected my SDS scanner, and it looks like ONLY the AAC is requesting the fan to run, even when the fan is running due to high coolant temp, on my scanner it STILL shows that the A/C is requesting it. It also shows that it is requesting 25% specifically. That speed rate doesn't ever change from 25%.

Test Results:

Doesn't Go over about 3.2V at any time... It is not the fan.

I tried to activate the fan with Component activation, and it doesn't work. In fact, as soon as I enter the "Engine Cooling Fan" area on SDS, the suction fan starts running on (25%) totally on it's own. When I try to command it ON, the fan turns OFF, and so does the ACC in the dash, it goes dark. Relay K26 also clicks ON, but doesn't seem to do anything.

I am fairly certain this is not normal operation, I should be hearing different fan running speeds all the time. As a result of this fan problem, the engine is able to still cool OK, but it is clearly not sufficient, and is running just a few degrees too hot ALL the time. This is very bad over the long term, and now that I am on my third coolant tank (and this one is already turning brown after only a month) I finally realized this. This can't be normal operation. If it is I'd be shocked, and likely just convert to a viscous fan setup.

If I pull the connector to the Coolant Temp sensor while idling, the fan rushes into life at high speed. (Coolant temp sensor is brand new)

My Error codes are as follows:

ESP Module:
1) C1140/8 Stored - Component N49 (Steering Angle Sensor) not initialized.
2) C1022/Stored - Fault in CAN communication with control unit N3/10 (ME-SFI Engine Control Unit)

ETC Electronic Transmission Control:
1) 132/Stored - CAN Communication with engine's system is sporadically disturbed or engine temp is sporadically implausible. (Pretty sure I caused this one by briefly unplugging the coolant temp sensor, strange that the Trans is reporting this)

BAS Control Module:
1) C1025-003/Stored: Fault in CAN communication with N47-7 (ABS Control Module). If no complaint exists, erase this trouble code.

Instrument Cluster:
1) B1040/Stored - Fault in CAN communication with control unit Engine Control Module.

Electronic Selector Module:
1) P1875/Stored - CAN Bus communication is not possible with other control units installed on this vehicle.

EAM:
1) B1086/Stored - CAN Bus Fault in communication to AAM.
2) B1040/Stored - CAN Bus Fault in communication to Engine Control Module.

AAM:
1) B1040 - CAN bus fault fault in communication to N10/1 (EAM).


Does anyone have any insight into what could be going on here? Thank you!!
 

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Registered
00' ML55 AMG, 98' E430, 95' S320
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91 Posts
Discussion Starter #2
Going to try replacing the ME (Engine Control Module) with a used unit, and see what happens. Will update with results.
 

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Dallas, Texas
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6,992 Posts
You need to rectify CAN communication issues before going any further. Used ME? How are you going to get around DAS?
 

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Registered
2003 C320 coupe, 2000 ML320
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630 Posts
You need to rectify CAN communication issues before going any further. Used ME? How are you going to get around DAS?
Ya, I'm thinking some of those CAN faults are from turning on the car with modules unplugged.. You might want to clear them and see if they come back..
 

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00' ML55 AMG, 98' E430, 95' S320
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91 Posts
Discussion Starter #5 (Edited)
You need to rectify CAN communication issues before going any further. Used ME? How are you going to get around DAS?
By using the "Car Prog" system. It is available on eBay, etc and it allows you to "clone" the info directly from the Motorola chip on the outgoing ME PCB. You can then "write" this data into the same chip on the "new" (used) ECU. This will work for sure, and is verified. It's not horribly difficult either. I can post some pictures if anyone is interested when I actually do it.

Still waiting for my replacement computer in the mail...
 

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Registered
00' ML55 AMG, 98' E430, 95' S320
Joined
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91 Posts
Discussion Starter #6
Ya, I'm thinking some of those CAN faults are from turning on the car with modules unplugged.. You might want to clear them and see if they come back..
I haven't turned the key or plugged in the battery with any modules unplugged... when I clear all the various codes, they don't come back for a while, usually a month or two. So it is intermittent, or at least the computer only spots the problem(s) intermittently.

Perhaps I should also mention that about a year ago, I had a Non-working low range condition. Push the LR button on dash, and nothing at all would happen. Replacing the Transfer Case module under the center console fixed the problem 100%. I opened up the old TC module, and it looked absolutely minty-fresh and brand new inside. Seems like these modules like to drop dead at times for no apparent reason.

The one thing I am having the most trouble with is figuring out where the CANBUS problems are originating from...
 
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