All fuses check, all are good. My bro in law will be coming with his computer (he's a Mechanic) to scan the car and I'll post back on here what's found.

Checked the IAT sensor was plugged in at least, it was fine. Although, upon removing it's connector, I had seen it was wet with a brown engine oil like colour to it's liquid. Not super thick, but definitely present.

 

You're talking about your charge air sensor, and not your crankshaft position sensor, yes? Shouldn't be anything like oil on your air temperature sensor.

 

the sensor located underneath the throttle body in the centre, underneath the air intake pipe. Only accessable by removing the air intake boxes. Is this the one you were referring to? Anything else you suggest I look at? I'll order and install a new sensor as you have suggested, too.

There was definitely a liquid on this connector 🥺

 

I think it's common to have oil vapor go through, but if it looks like it's gunked up that could be your culprit. $25-28 bucks.

 

ok. Wasn't gunked. Just wet, essentially. Doesn't look like its in stock locally. Online order it shall be. I'll report back soon hopefully. I'm just itching to feel that supercharger for the first time!

 

Not trying to discourage but your IATs looked to be between 20 and 30C. That's not going to prevent engagement.

 

It will if the sensor is defective. This is another reminder that the small investment in a STAR system goes a long way when owning a Mercedes.

 

Here's what was scanned. Erased codes, driven again, that same code came up to do with it shorting. Advice? What am I looking at here?
here's the scan results guys ..

 

Have you looked at the connector to the magnet? It's behind and to the left (as you face it) of the pulley/clutch on front of the supercharger. That's definitely step #1 as you could have a bad connection, frayed wire etc.

Haven't seen too many magnets go bad, but there could also be a bad spot in the wiring elsewhere. If you do end up finding a magnet problem that doesn't affect the supercharger mechanically, just swap in a fixed pulley and tune, it will feel like you gained 300 hp coming from not running any boost

 

Wiring is good. Clutch was activated and clicked/moved when told to do so with the software/scanner tool.

I'd rather keep it stock and fix the issue.

 

Ah, that is odd indeed. If no one chimes in soon I'll be back home tomorrow night and see if I can look up the WIS fault info for that code, it should give you the diagnostic procedure tree and reasons for that fault.

 

Thank you. I really appreciate your help so far. It's surprising, a search online for the codes doesn't really bring up much information.

 

It's a general electrical fault message, with three guided tests through WIS. The key thing is whether the clutch is activating.

 

It clicked and moved, but did it actually engage or could it be slipping?

 

with the scan tool, it clicked and moved. We tried to get it to do it a second time but it wouldn't. My bro-in law said that's not an issue if it didn't react a second time. Could the MAP sensor or IAT sensor be causing this issue?

 

Difficult to say. We cleared the faults, I drove it immediately, and immediately felt no power. So, it didn't require a WOT or anything for it to stop working. So I think slipping is not an issue, at this point at least.

 

Can't you drive with the scan tool and see if it is commanding the clutch to engage? That would rule out a long list of issues and focus on the magnet and pulley/clutch. Though maybe wiring is still in question.

Also you probably need to clear the fault as it may disable the clutch to protect itself once it senses an issue.

You should also measure the resistance of the magnet coil. The ECU is expecting 2-3.5A so resistance at 14V should be 4-7 ohms.

Sorry one more question. What tool is that? Is it a Launch x431? I ask because you described bidirectional control and it's clearly not STAR...inquiring minds want to know.

 

@kevm14 as a precaution, I will be changing the crankshaft pos sensor, IAT sensor and the MAP sensor. Should get the parts next week.

- How do I go about measuring the resistance?
- Am I able to provide 12v directly to the clutch wiring and should see it click?
- Are there any relay's involved that I can check to do with the circuitry?

I'll take a good look at the wiring to see if there's any damage.

 

Somehow I missed the resistance spec. I swear I checked. Anyway it says 3.5-5 ohms....just use a regular DVM on the pins.

You could also do a bypass test on the pins to the clutch coil with 12V but use care since the pins are likely very close together.

It looks like the control for the clutch coil is directly from the ECU.

 

You can measure resistance with a simple voltmeter, just unplug at the magnet and test ohm reading between the two terminals. If you've already seen it click when commanded applying a separate 12v signal won't tell you much more, and I don't believe there are any relays for the clutch specifically, at least none specified on the relay and fuse chart. If it did and was bad, I wouldn't imagine you would have heard and seen the clutch engage when commanded.

If you have a couple of short wires you could rig up something to keep the circuit closed and tap into those wires to measure amperage with your voltmeter. That's basically what those MB-specific socket boxes do at the ECM.

Those sensors are all wear items and potential problems on our cars, so it will be good to at least check those off your list. Crank and IAT are easy, the MAP is a knuckle breaker but doable in the car. I would see about running those tests on the magnet first though, if you are out of parameters on either ohms or amperage then you'll know it's something internal to the magnet and the SC has to come out. I say do this before because replacing a MAP sensor is a 1 minute job with the SC out vs an hour of cursing with it in the car haha.

 

Knuckle breaker... And cursing. Two phrases that have 'german vehicle' written all over them. Noted.

Ohm reading is at 4.4, lowest was 4.1.

 

Next thing I would try is leave the clutch unplugged and try actuating it after resetting codes. Or even try driving it. See if the same code comes up or a different one. The resistance value seems normal.

 

At WOT, from standstill in "S" mode
hi.

Didn't want this thread to die out like the others have done, which is why I'm struggling to find much information on my issues.

So here's the update:
New MAP sensor, new air intake sensor, new cam position sensor, new ambient air temperature sensor and all relevant gaskets have just been changed. Took it for a run and the attached image is the results. So looks like I'm still not producing any boost. But ... I haven't yet reset any of the computers with that gadget thing. So next step is to reset and clear the codes, drive it and see what happens. I'll report back my findings...

 

I've been curious, thanks for the update. Definitely reset everything and report back, even if you don't have a proper scan tool just do an overnight battery unplug. Fingers crossed for you!

 

Guys, another small update. I couldn't upload a video on here but I have tested the clutch on the car (whilst warm) by wiring from the small battery at the front up directly to the connector on the clutch. It clicks, and moves around perfectly. I attempted it several times, no issues with it at all.

I'm yet to reset the errors but I just wanted to report this finding back to you guys.