Hello all! I bought this car a couple of months ago and seem to have a mess on my hands. I'm going to be straight and to the point: I suck at mechanics and in-depth electrical troubleshooting. I can barely read this wiring diagram from WIS.

If someone could take a look at this video of what my wiring situation looks like on the the AdBlue module and provide some feedback as to what in the world the previous owner was trying to do, I'd greatly appreciate it.

Here's the video: https://www.icloud.com/iclouddrive/0...8OoA#SCRwiring
Here's the wiring diagram from WIS: https://www.icloud.com/iclouddrive/0...WDn4hamd7A#WDS

Edit: I'm going to add the multitude of things I've experienced, things I've replaced, etc.:

• Got auxillary battery warning shortly after purchase - replaced with Duracell AGM
• Multiple rear lights out - replaced rear SAM
• Intermittent ESP/ABS inoperative, car wouldn't could out of Park - dealer replaced front fuse box
  • Issues persisted, now including PRE-SAFE inoperative, cruise control, etc. - I replaced steering column module
• Sirius will not activate. Sometimes I get the Preview channel but no audio, sometimes I get "No Service"
• Both rear left Parktronic sensors are saying they're bad
• Interior lighting is very unpredictable:
  • Sometimes interior dome lamps stay on for only a couple of seconds after ignition off, other times they're normal
  • Driver's illuminated door sill flickers (sometimes)
  • Sometimes interior dome lamps don't recognize the door is opened
  • Sometimes cluster tells me "Don't Forget Key," other times not
• Neither front door locks (with central locking, with mechanical key, with Keyless Go, or with remote)
• No horn with alarm event

I've gotten several codes I'll try to post later RE slow or no- communication on the CAN bus. I can't imagine that every. single. computer. can go **** up and the janky wiring on the AdBlue control module concerns me

Edit 2: These are the codes I'm getting from iCarsoft, I get a few others from BlueDriver (Attached)

ECM:

1. Component R9/1 (Cylinder 1 glow plug) has Open circuit - Current and stored

SCR:

1. The output for the heating element 'AdBlue tank' has an electrical fault or open circuit - Stored

ESP:

1. No CAN message was received from control unit A1 (Instrument Cluster) - Stored
2. No CAN message was received from control unit Engine control module - Stored
3. Chassis CAN bus: CAN Controller: CAN bus OFF - Stored
4. No CAN message was received from control unit N93 (Central gateway control unit) - Stored
5. No CAN message was received from control unit N80 (Steering column module) - Stored

TPMS:

1. Signal transmission between at least one wheel sensor and N88(TPM(Tempomat) [EDK] control unit) is faulty - Stored (x2) - One wheel noticeably missing TPMS sensor

SRS:

1. The resistance value in the ignition circuit containing component R12/13 (Driver airbag ignition squib 1) is too low - Current and stored. - Maybe didn't plug in all the way when replacing steering column module?

Front SAM:

1. The component or the signal line to the component E1e14 (Left outer turn signal lamp) has Short circuit to ground or open circuit to the component E1e6 (Left side marker lamp) has open circuit or Short circuit to ground. OR the component or the signal line to the component E6/1 (Left front side marker lamp USA) has Open circuit or Short circuit to ground. OR this fault can be ignored and erased. - Current and stored - Both mirror LED signals need to be replaced, I know
2. The component or the signal line to the component E2e14 (Left outer turn signal lamp) has Short circuit to ground or open circuit to the component E2e6 (Left side marker lamp) has open circuit or Short circuit to ground. OR the component or the signal line to the component E6/2 (Left front side marker lamp USA) has Open circuit or Short circuit to ground. OR this fault can be ignored and erased. - Current and stored - Both mirror LED signals need to be replaced, I know

Rear SAM:

1. M14/9(CL right rear door motor): Short circuit to ground or open circuit - Stored
2. Component E4e1 (Right turn signal lamp) or the line to the component has a short circuit to positive or open circuit - Stored

PARKTRONIC:

1. A43b9 (Left inner sensor, rear bumper): Sensor is faulty - Stored
2. A43b10 (Left outer sensor, rear bumper): Sensor is faulty - Current and stored

Door Control Module - Front Left

1. Component M14/6 (Left front door central locking motor) or lead has Short circuit to ground - Stored

Door Control Module - Front Right

1. Component M14/5 (Right front door central locking motor) or lead has Short circuit to ground - Stored

 

Here's the dealer's explanation for replacing the front fuse box:

 

I haven't looked at the video, admittedly. Before getting into all the modules and codes, how's your main battery? Do you know when it was last replaced? Weak main battery will throw a bunch of random codes which aren't necessarily a problem individually.

You can check voltage in MB II. I have a gas GL and for battery values I go to V8 section and read the current data stream. You can go to the V6 section too, it captures similar data stream values as far as I could tell

Go to the section with the motor and preferrably all accessories off, ignition on, observe voltage,
then start the car and observe the voltage during crank,
then observe voltage when the motor is running.

Edit: I forgot to add that the voltage will increase gradually when you start the car. Give it a few seconds to settle at the high values, and it will fluctuate a little, but should be relatively the same value. Let the car idle while you are looking at the values, no need to rev the motor.

You're looking for
~12.4V with motor off, it might be higher
14+V when the motor runs.
The crank voltage will drop below 11V probably. At least it does on mine, 5.5L gas. As low as 10.5V, I have noticed. The chances voltage was observed by me with a new Interstate AGM battery when I installed it about a month ago. The diesel might be different, I'm not sure.

 

Thank you so much for this info. I'll look at it tonight and let you know. While it's still behaving itself (relatively) and the OM642 oil leaks aren't readily apparent (yet), I'll probably sell it and let it be someone else's problem soon.

 

Lol that's one way to go. Electricals on German cars! I blame Bosch and Siemens.

You can also clear all the codes that are currently stored, turn the car off, start it and scan again to see what might return. I think sometimes these cars act up with just having codes with status "stored" in memory (events which happened in the past) and not "current" (events occurring at the time). The pressing concern would be codes with "current" status. If status is "stored" only, it's OK to ignore in the short (or long) term.

 

I'll clear them again and see what returns. I'm down from the 101 I had! There's just too many weird **** with this car for me to be able to justify keeping it. I had plans to rip out the BlueTEC system completely and delete the DPF, EGR, etc., send the ECU off for flashing. But then I'm sitting here questioning "why?" I've still got 20+ hours of labor to fix the oil leaks and an electrical system that rivals the worst British-Leyland (probably not MB's fault). Diesel's dead for regular passenger-car use.

So, the search begins for a post-facelift gas 164 with every option-box ticked.

 

I wonder if there was any water intrusion in the specimen you have. If water leaks in and corrodes the SAMs, you're in for all kinds of treats and troubles. Sunroof and rear tail light rubber seals tend to be the usual suspects for water intrusion. When you replaced the rear SAM, did you notice any signs of water in the well where it was located? Or signs of corrosion on/in the SAM? Check the fron battery hole/well for water signs too. If you have the old SAM, open it and inspect for corrosion as well.

It seems like a lot of labour labour up front to fix what's not working. The older I get, the less extra work I like/have to do, the better. I've started to like and appreciate conveniences more and more. Said from someone who picked up a 10 yr old car with a few known problem areas. HA!

 

Codes cleared and attached. I attached two files, both from BlueDriver instead of the MB II since it's just a lot more convenient to clear all the modules at once with the BlueDriver and it seems to give the exact same information, and in some cases more. First file is with engine on (before driving). Second one is after driving ~7 miles. I forgot to measure battery voltage. I'll go out there later tonight or tomorrow and check it out.

 

There weren't any obvious signs of water intrusion near the SAM, but there was actually a small pool of water to the left of the AdBlue tank (under the styrofoam) that had submerged several ground wires. So, I'll await everyones' guffaws.

Once I drained it, dried it out, and leak tested over several weeks I haven't seen any more water. I also haven't really driven at any speed during a rain storm. Someone told me there was a vortex that would develop and suck rainwater in through the faulty taillamp seals. But the thing is my seals were replaced under recall back in 2009 (I've got the warranty work from MBUSA) because it was optioned with the power-liftgate and the seals were of course installed incorrectly.

 

I'm not familiar with what the front SAM is responsible for in the ML, but it looks like it might be a problem. There should be some info on the front SAM responsibilities on this forums, or perhaps someone who has the know-how could chime in. I think it is located in the MLs main battery well. I would check it closely for corrosion. It may be a good idea to also remove the main battery and have a close look at the well for water. You'd may have to remove the battery to get to the SAM. On my GL it's tight with the battery in place.

Main battery removal is simple to do, but a bit of a pain with the location under the passenger seat. Move the seat all the way forward, all the way up, and lean the back rest all the way forward to give your head and neck space to hover over the well. Disconnect neg terminal first, and connect the neg terminal last. Wrap the neg terminal in a zip lock bag and tape to avoid accidental contact and spark. I'm going by the GL battery job I did, but it should be similar for the ML.The job is done with 10 and 13 mm sockets and extensions. If you have swivel extensions, the posi terminal nut will be easier to loosen. The angle of the nut is slightly upward. For the two bracket nuts, use painters tape on the 13 mm so the nuts will stick and remain in the socket when you take them off and put them back on, unless you have the extra lean and long fingers of a piano virtuoso. Or a magnet to fish them out. There are youtube videos showing the process. I looked at a couple to familiarize myself with the "beast", although I've done a few batteries in other cars, but none on MB and under a seat, up till last month.

If tail light seals were weplaced in 2009, they could be wearing out by now. It depends on what weather conditions the vehicle was subjected to before you got it. You can test the current ones with water hose or pressure washer and the hatch closed. Be prepared to catch and dry any intrusion quickly to avoid unnecessary damage to electricals.

Lift gates on SUVs and wagons have a different weather zone back there when the cars are in motion. Some day they may come with a dedicated meteorologist too.

Still, it could be a weak main battery problem. The voltages should shed some light. If you remove the battery, look at the date on it to determine the age.

 

I did leak test with high pressure around the usual culprits and didn’t find anything. I’ve got WIS so I’ll check on the front SAM’s functions once there’s a lull in one of my Teams meetings that should’ve been an email.

I was going to take my 166 to the beach this weekend but believe I’ll take the 164 and see how she does. When I get off work I’m going to meet a buddy so will do the battery test, see what I get, and update the post.

I’m tempted to say the various ESP and Pretensioner codes are a result of either me stupidly sitting in the car with the belt buckled or just standard PRE-SAFE checks that BlueDriver doesn’t know how to interpret. I definitely have a self-inflicted airbag issue from replacing the SCM, I’ve just been too lazy to go through the rigmarole of taking the airbag out again and diagnosing. One shop said I could’ve messed up the clock spring...

 

Drove it about 50 miles yesterday (codes attached). Battery voltage checked out okay. I even managed to get ESP to engage itself, so ::shrug::. I'm gonna try to sell it and get a gasser. I wanted a project (that's why I bought it) -- but not this much of a project. Suppose I should've done a bit more research on the OM642 before deciding "it'll be just like the OM617 -- only better!"

 

Let's hope the bext one isn't so problematic. The odes you're seeing are electrical related more or less. I'd take the scanner and plug in the prospects to check their condition before buying one. Ask for an MVI from the private seller or MB dealer too, to get a sense of the maintenance on the vehicle. Good luck!

P.S. a PPI woild also be a good investment to find out what's currently wrong with the car before buying it, but scanning with your own scanner is a good alternative.

 

Agreed. I actually bought it from a wholesaler off eBay. I'd been looking for an optioned-out 164 with for months. Drove up to VA to pick it up and didn't see anything other than the rear SAM needed replacement and it was obviously overdue for B service. I had loaned my code readers to a buddy so that wasn't an option, picked up a semi-generic one from Best Buy on my way up there but it didn't pick up anything except the AdBlue heater.

I even took it to the dealer in Richmond on the way home and I should've known I had a problem on my hands when the SA just gave me a blank stare. I'm sure her mouth was open behind the mask.

You live, you learn. It's still in much better shape than my usual projects (first-generation X5s)!!

 

Update: I couldn't take it anymore. I needed the airbag clock spring replaced or repaired and a telematics/COMAND update before potentially selling it, so it's at the dealer again. I asked them to quote me a price on cleaning up the wiring on the SCR module and letting me know their best guess on what was being attempted.

After the experience with my last SA, I went to a different dealer and this one actually seemed to listen and hear me, so fingers crossed!

 

Did you ever figure out if replacing the front SAM was the culprit? I have a weird issue:I was driving and everything was normal as always, but at one point the car lost it's power and did not accelerate well. Also I've got a message with thermometer (assuming overheating).

So I've stopped and shut off the engine. Started the engine and got check engine light.

Then I had to drive another 5 miles and sometimes can barely accelerate to 30 mph.

The car feels like she has no power.

Found a thread about checking fust box on passenger side under hood. It is the fuse between the two relays on the side closest to the oil filler cap. The 15 amp fuse was blown. Replaced fuse. Problem still existed and blew the fuse I just replaced. I think I read someone knew how to make the "m55 intake flap actuator" stay open, but also have to insert a resistor somewhere. Anyone know where to find the flap actuator, and is it something that is difficult to get to an replace?

I have a ob2 scanner. Fifteen codes. My reader is generic. Is there a better reader to use?

Thanks in advance!

 

Front SAM is not the culprit. It sounds like you're in limp home mode. You definitely need to invest in a better code reader. Many folks recommend the , but I personally have found that is just as capable at basic diagnostics and has the added benefits of being less expensive, Bluetooth, and works with cars other than MB, while still communicating with all the MB modules.

I think you may be looking for this post on how to bypass the swirl flap motor.

I've decided to just keep mine, do the oil cooler seals, oil filter housing gasket, and delete EGR/DPF/SCR and whatever else is left of the emissions nannies (to prevent future problems, since it's my understanding the OM642's main issues tend to stem from the emissions equipment) and hopefully that'll get me through my next high mileage award.

 

I live in California, where they do smog inspections. I don't think I can jerry-rig it if its emissions related, as they'll likely catch it.

That said, is the little servo motor thingy a difficult task? I am by no means a mechanic, but have tools and do lot of home renovations and stuff like that. I used to be an electrician 25 years ago. So, I have skills, but not sure if replacing that motor thing is something I should attempt. I called my non-dealer mechanic, and he said it was a five hour job.

I just go a recall letter about the Mercedes and the emissions scandal lawsuit. So I would be a fool to go install something propping those flaps open, since if they caught it while doing the recall, I might not qualify for all that work. Maybe I'm wrong.

If I pay the 5 hour ransom, is it worth having anything else done while he has the manifold apart? I wish I could call you up - as it sounds like we have the same exact car! 2009 ML320 Bluetec. I too, want to just get the car working and sell it...

 

I'm not mechanically inclined in the least, I don't even know the purpose of the swirl-flaps -- but they are emissions related and unfortunately are not part of the AEM (aftermarket emissions modification) resulting from the lawsuit. This is my first diesel and I'm regretting I bought it. The OM642 engine's problems are well documented. I suggest starting here. That guy is in Sacramento, not sure how far that is from you but he seems to know his stuff.

Bypassing the swirl flap motor with the resistor doesn't appear to be too involved. Remove connector, insert resistor. But BlueTEC works as a system, and every component feeds data to the others. If I lived in California -- and I love California, don't get me wrong -- I'd be terrified to own an older BlueTEC simply because of the smog checks every two years and the costs involved in repairing the equipment. Yeah, Mercedes says they're extending the warranty on the components they replace, but what about the components they're not replacing? You could always ask around and see if there's a sketchy shop somewhere that you can slip a couple hundred bucks to for a pass, but that's up to you. The settlement money from the lawsuit isn't enough to persuade me to accept the AEM -- potentially at the expense of power and/or fuel economy, which is why I'm just deleting it all.

If you love the car and have family or friends in another state, maybe see if you can re-register it there. You could also try just selling it to CarMax and let them send it to auction in another state

 

Funny you mentioned CarMax. I thought the same thing.

I will have them do the AEM. Maybe that will fix all the emissions stuff and I won't have anything to worry about.

If it were not for the limping, I would still drive it. I will have to have it towed to someone who can fix it. This car has been nothing but a money pit, meanwhile my other SUV, a Mitsi Montero, keeps plodding along without any issues at 21yo and 235k on her.

Sad that MB can't seem to be able to make a car that is worthy. I mean.. my MB doesn't even have a 100k on it. Mitsi has almost 2.5x the miles on her.

 

The Mitsubishi didn’t have to contend with being a diesel in a vastly different environmental landscape like the ML. Make sure to read the article I linked to on the BlueTEC OM642 engines. If you do choose to have everything repaired, it may be smart to do the add-ons that Stephen talks about to save yourself headache down the road. It’s a good engine, just with some peculiarities and faults caused required emissions equipment, and then throw the then-new BlueTEC into the mix and it’s just… no wonder Volkswagen just said “screw it, we’ll just cheat the tests.” Granted Mercedes cheated as well, but not nearly as egregiously as VW. That’s why VW was forced to do buy-backs and MB is able to just replace a few components and update the software. Diesel was on life-support in 2009 for a variety of reasons, mostly out-of-touch lawmakers and unrealistic emissions standards. The emissions scandals were just the nails in the coffin.

Don’t believe CarMax can do the AEM. Only MB dealers.

 

Sorry about the confusion. I meant I should just take the car to CarMax and take the check and run.

MB should not have tried to make a diesel if it was nearly impossible to do so. I'll never buy another MB because of this headache they have caused me.

I found a guy that works on MBs, who isn't the dealer. I'll never bring my car there for anything other than a warranty problem. I just don't trust them.

Thanks for the link to Stephen's MB. I'll check it out.

 

Hi. The one SCR code is very likely for the DEF in-tank heater. The MB dealer will replace it under a n/c Goodwill Warranty if you're getting other work
done. And they will update the software in the SCR module (and should also do so in the CDI module).

From the video, it looks like previous owner tried to install an SCR delete mod which requires tapping into the existing SCR harness. You will have
to remove the grey tape to have a better look at the small board (can likely find instructions online for it). I would just remove it along with the wires
attached to it. The long thick blue wire and two small green wires to that mod are definitely not original to the harness. The thick orange wire is likely
part of the harness. You or someone can repair the harness with butt connectors, some soldering and heatshrink. Doesn't sound like it was installed
right if you're getting an SCR error code.

As for the TPMS, I would go to Costco if you're a member. Likely to be quite cheap or free if they can't replace the one bad sensor. The battery in them
only lasts up to 10 years.

The back of your radio unit may have a bad connection?

It's possible there is a problem with glow plug one, or a fusible link is gone in the glow plug relay/controller. There
likely is a test for it online somewhere. The W166 uses ceramic glow plugs that are unlikely to ever need changing.

The whole driver front door sill plate you will need to replace as the LED can't be changed. Check out the wreckers.

As for the ESP light, you could have dirt around one or more of the ABS wheel speed sensors that go to each wheel hub.
Problem is the rotor dust shield would be in the way to see anything. You could try an air compressor and blow gun
nozzle to clean up behind the shield. Also, it could be the brake pedal elec. switch (trouble shifting out of Park (or small
aux battery getting low), can cause ABS/ESP to shut off, rear brake lights will not stay on, you have to pump brake pedal
like a non-ABS car).

The sensors in the front and rear bumper are sensitive to dirt, and need to be kept clean.

Did the RevETR L+R, and SRS codes come back after charging up/replacing the main AGM battery?
The battery draining below 12V can cause these codes.

Regards.

 

Yeah, I gathered as much. Doubt very seriously the dealer will do anything about it and honestly, it's not worth my time if I'm going to do all the deletes.

I was thinking along the same lines, that it was an AdBlue emulator. I just didn't bother tracing the wires.

It needs two new rear tires anyway, so I'll add this to my list. Thanks!

I'll check this out, but one issue I've discovered is that the Radio ID listed in Mercedes Me is different than the Radio ID on the COMAND module. It wasn't until Telematics was updated that this even started showing in Mercedes Me (even though the rest of telematics doesn't work). I was thinking maybe it needed a COMAND update, but the dealer "strongly cautioned" against an update because there was a "high risk" of it bricking the system.

It's at an indy shop now (finally found one I feel I can trust), so we'll see what he says

This was actually diagnosed by the dealer at the same time as the door locks. It came back to the door lock switch reading implausible "at times."

ESP and PRE-SAFE no longer issues. That was all solved by replacing the SCM and then reconnecting the airbag properly.

I attempted the WD-40 trick a couple of times and so far have managed to only bring back one parking sensor.

That was fixed by plugging in the airbag, which I had not done after replacing the SCM.

 

If anyone is following the thread or has the same problem in the future, hopefully I can spare you the wallet hit of all the dealers and independents who will just replace modules ad nauseam.

I finally found an independent I could trust (Wrench Automotive in Gastonia, NC for anyone in the Charlotte metro like me) -- and while he was R&R'ing the tired ol' OM642 that hadn't seen anything other than dealer maintenance in 155k miles, I asked him to trace the blue wires back from the SCR module after he started getting the same CAN bus faults RE ESP, PRE-SAFE, SRS, and "Proceed to workshop without shifting gears."

Sure enough -- they terminated in the passenger side kick panel. Look at this rat's nest. Likely from SCR emulator previous owner cut out before turning over for repo. He said several were CAN lines.