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Hi team - I am replacing the crank position sensor in my W221 S600 and I own the STAR computer. In the steps it says that I must initialize the sensor using STAR DIAGNOSIS
But when I go in the STAR tool and the control unit adaptation area, I can't find where to do this. Anyone know where in the STAR tool I actually do this step??
if its real, is this an element in the weird and wonderful misfires that plague these models
to be clear, there are no misfires. I'm replacing the CPS because sometimes, when hot, the engine won't start on the first press and you have to press the start button a 2nd time and when I pulled the code, it said "crank position sensor"
I replaced mine a while back... have not found anything in DAS for initializing it though. It also did not fix the problem -- like you, once in a while I press the button, there's a sound of a relay closing, and nothing happens. If I hold the button in for a few seconds it starts normally.
Hi team - I am replacing the crank position sensor in my W221 S600 and I own the STAR computer. In the steps it says that I must initialize the sensor using STAR DIAGNOSIS
But when I go in the STAR tool and the control unit adaptation area, I can't find where to do this. Anyone know where in the STAR tool I actually do this step??
thanks in advance!
Does the sensor come with its own “computer” to be replaced with it? I would not think it does.
CPS that I know from my past vehicle was a simple sensor that reads fly wheel teeth and gives simple ON-OFF pulses. If it is same kind of a sensor I don’t see any reason it should be somehow “coded” for the car.
If you get the part from a dealer they may, depending on the dealer, just tell you the story in hopes to get a few hundred $ for the 15 minute job to install it.
Can anyone explain the process of replacing on the M275 engine. Any tips? I know where it is and how it comes out but it's really tough to access it with such a small amount of room.
I ended up cobbling together a VERY long 1/4” drive extension, using electric tape at joints to keep it from separating. I threaded it down from the top with one hand while guiding it from below with the other. Patience and a magnetic retriever were required.
I remember reading a lengthy document in WIS stating that: after replacement of the CPS or engine mounts, flywheel adaptation reset is required.
From what I understood, resetting adaptations, leads to a smoother drive train and better knock-sensor operation.
Last edited by Solo wing; Oct 4, 2020 at 12:29 PM.
As I see it any 'adaptation' done is putting lipstick on a pig. Crank position sensor works or it doesn't. Should there be any difference between new and old the electronic magic will learn and change all by itsself. Which reminds me. My car needs another set of engine mounts. Sigh.
the idea of the CPS is to tell the engine what position its in, is it not. Its not just a signal to say its going round or sending a speed signal to the rev counter?
If its the former, the actual position…. being their top flight model they might care if the position is the exact one, rather than some approximation (which would do for the simple stuff). Now we can pretend you can time off the cam sensors, but then these day dream an approximation, based on the variable slop from the designed to fail cam chain and chocolate idlers. So not the best place for exact ignition timing.
Thus if we want it spot on, we might choose to inform a posh ECU that knows the difference between 0.125 of a degree vs that of a mass market engine where it wouldn't know if it was this side or that side by 2 degrees, exactly where both the pistons are in relation to the cylinder head (as told by a new sensor) and again we might want to set up the cam slop to the pistons at the current amount of stretch in the cam chain / vague understanding from the cam sensors magnets. That way the clever computers can ensure it all stays tip top. So I can see on a decent engine you want to work well, the idea is really sound... its just they don't care on base shopping cars
I know that one of the uses of the CPS is to detect which cylinder is misfiring. The engine doesn't have a sensor for each cylinder, yet, in the case of a misfire, the ECU will throw a code for the offending cylinder. The CPS can detect this by calculating the exact acceleration and deacceleration of the crankshaft.
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