The CKP does not have a fuse dedicated to it. The CKP generates its own signal to the ECM.

As for the injectors, check fuses #26 and 19.

 

Sorry forgot to mention that, I've already checked all the fuses in fuse box in engine compartment and by passenger kick panel.
Injector fuses are ok.

So none of the two wire going to the ckp do not produce any type of current at all?
Now i'm really at a loss.
Correct me if i'm wrong but doesn't the ckp send out a pulse signal based on the magnetic end receiving magnetic contact on the teeth?
Does this car have an overload protection relay?
Now I really sure I need a wiring diagram. Please help......

 

....So none of the two wire going to the ckp do not produce any type of current at all?
Now i'm really at a loss.
Correct me if i'm wrong but doesn't the ckp send out a pulse signal based on the magnetic end receiving magnetic contact on the teeth?
Does this car have an overload protection relay?
Now I really sure I need a wiring diagram. Please help......

No OVP on your car - too modern for that. No 'current' produced either.

As stated above, the CPS produces a chain of pulses for the ME-SFI control module (N3/10) also known as the CPU. These pulses are analysed to detect the TDC for ignition timing.

There is an induction coil inside the CPS (L5). Its resistance should be 'somewhere' between 0 ohms (short circuit) and infinity (open circuit).

Incidentally -it's not a good idea to check for spark plug firing outside the engine (as of yesteryear) with modern electronic ignition systems. My WIS says that it can damage the CPU.

 

CPS signal on the wire can be read by an oscilloscope if you have one.

Have fun.

 

Maybe you can post your codes.....
As 43 explained a healthy CKP generates signal to ECM which sends a negative to the injectors. If your CKP is malfunctioning (it doesnt matter when you have changed it) your injectors will not fire.

 

Hey guys thanks for the reply.
He is to answer your questions.
NO oscilloscope.
My scanner doesn't read RPM's as its a cheap code reader only.
I checked for a ground pulse to the ignition coil and there isn't any I do have power but no pulse which lead me to believe the ckp or crank position sensor was bad or not getting signal to send the pulse back to the computer.
Checking for spark with coil and plug out is the only way I know how to verify that a car has spark.
Is their another way?
I'm confused now doesn't the crank position sensor (CKP) send the signal to the ECM for the firing of the Ignition Coils?
And the Camshaft Position Sensor (CPS) send signal to the ECM to fire the injectors or do I have my abbreviations confused?
I'm out of ideas and that's why I'm here to find help.
Please give me guidance o great ones :bowdown:

 

Keyhole,
Thank you for the diagram and I see that their is no can or relay between the CKP and ECM and that's what I was looking for to be sure as someone told me that their should be a relay for it but I see that they were wrong.
So question even though I have no oscilloscope I still should be able to get a ground signal from the ECM to the CKP and then I should see it pulse a ground power back to the ECM right?
I will test the resistance on the CKP sensor but can it go bad within a year?

 

....as someone told me that their should be a relay for it but I see that they were wrong.

The trouble with advice from 'others' is they may know something about their own car, which can be quite different to yours - even if it is also a Mercedes. However, I wouldn't expect any sensor (on any engine) to have a fuse or relay in its output to a control module. Why would it? A sensor cannot damage anything.

So question even though I have no oscilloscope I still should be able to get a ground signal from the ECM to the CKP and then I should see it pulse a ground power back to the ECM right?

No - it doesn't work like that, the signal is 'floating'. The output from the Crankshaft pos. sensor will be a high frequency signal with the engine running (f = number of teeth x rpm) that you can only see with a scope. Nothing will be generated with the engine static. As far as I know, this sensor is only utilized at engine start.

The Camshaft pos. sensor also generates a pulsed signal from a Hall Effect sensor that passes over a metallic segment on a camshaft sprocket. This is used for timing the engine ignition & fuel injection.

Why both engine sensors are needed I'm not sure, as the crankshaft and the camshaft are synchronized. Maybe an expert can explain that?

I will test the resistance on the CKP sensor but can it go bad within a year?

Was it a cheapo?

 

Did you buy a bosch sensor a year ago? Cheap sensors can go wrong fast....If it was bosch, all I can say is shit happens..........
Then again, we are speculating that the CKP is malfunctioning. Without the codes it is guess work.

CKP sends signal to ECM ( "handshake"). After ECM is satisfied that the CKP is functioning properly it sends a negative to the injectors.

 

Heat is destructive to any sensor, especially the CkPS. And where is it located? Right at the back of the engine on driver side (U.S.) subjected to all that heat.

If I had a no start situation where the vehicle turned over, that's one part I wouldn't mind throwing money at first, regardless if I'd put it in a year ago or not.

 

Droopy, if your code reader didn't find anything please describe the history of your starting problems.

Like how long ago was the first time you had long-crank-no-start? Has it started before on the 2nd or 3rd attempt? How often does it happen? Why did you replace the CKP sensor a year ago? Were you having starting problems then?

 

Here are the fault codes I recovered.
P0305- misfire cylinder 5
P0302- misfire cylinder 2
P0303- misfire cylinder 3
P0305- misfire cylinder 5
P0302- misfire cylinder 2
P0306- misfire cylinder 6
P0300 - random misfires
I've cleared them all.
Vehicle just cranks but doesn't start.

 

It was a napa brand cpk sensor.
History if vehicle is bad.
It was Jamaicanized no disrespect to anyone but the wiring was has been hacked.
Either way it was running good last year then turned off I let cool or came back after an hour and it started but no codes.
The one day it just cranked and didn't start so I checked fuel pressure and it was good then I check for the ground signal to the coils and it had none so I just replaced the ckp sensor with a Napa brand one and it started.
Now it turned off once again about two weeks ago and last week parked fine but seemed to be sputtering left it as it was late then the next morning it wouldn't start just cranks and now I'm here.
I did as before which was check for ground signal to the coils as I know that's what causes them to work but again I have none so this time I figured Id check to see if I have a signal to the ckp which I found none and them lead me here for expert advise. :thumbsup:

 

I advise you to replace the aftermarket CKP sensor with an OEM or Bosch one.

I suspect that new spark plugs are well overdue.

 

I will find an OEM or Bosch and see what happens.
Also yes your prob right cause I've never changed the plugs since I've had it so more than likely than do need to go.

So then just confirm their is no way with either a multimeter or light tester to see the signal power or ground going to the ckp sensor as I just want to be sure its getting a signal from the computer?

 

If you have a scanner or code reader that shows RPM's, then crank the engine for 10 secs. and see if the RPM's register to at least 200.

 

Hey guys thanks for the information and absolutely im no electrical engineer and def don't claim to be either.
Thanks for the info and I'm order an OEM crank position sensor.
I will post my results once I receive it.
Thanks again :thumbsup:

 

Hey guys sorry for delays in reply.
I've received the new OEM crank position sensor.
Did a resistance test on both and yes theirs a difference, Aftermarket is like 1.6 and OEM is like 2.? cant remember but its installed and the same problem is occurring.
So I ordered a Autel MAxidas DS708. Just received it and ran a short test.
Car had several fault codes but the only once that I believe to be related to the problem and the only ones that returned after a master clear off all the fault codes are these.
B1040
B1086
C1038
C1212
C1210
Can any help me find terminal 30?

 

None of the above codes have anything to do with hard starting or the CKP Sensor. They are probably there because of past intermittent problems and were never cleared.

"B" Codes are generated because of problems in the AAM, Instrument Cluster, A/C, etc. and they must be cleared separately, and cannot be cleared through the ECM.

"C" Codes are generated because of problems in the Traction Control System and they must be cleared,..............same as above.

Circuit 30 is located at the fuse box.

 

For what it's worth: I had a highly intermittent no-start. The car would shut down at random, then run for three weeks without issue and then do it again. Sometimes it started after waiting a little bit. Only in the end did it become a permanent no-start.

After lengthy troubleshooting it turned out to be a bad ignition switch. The +12V power for the ignition coils comes directly from the ignition switch and not from the Term 15 relay. My ignition switch was in a state where it kept the relay for Term15 powered through the AAM but wouldn't supply enough current to produce a reliable spark in the coils packs.

I only found it by looking at F26 with an oscilloscope and the studying the schematics. On the scope I saw the drop-out for the duration of the coil dwell on the order of milliseconds. With the new electrical part of the ignition switch installed all was well. I opened up the old switch and there was some sort of charring on the contact for Term15. It caused poor contact.

Ingo

 

Ok i've rechecked the ignition coils and I have power to the coils but no ground pulse.
Ive checked the terminal 30 and power is ok.
Their was mention of the ignition switch but only provide power to the vehicles system right?
If it also provides ground power then can someone give me a wiring diagram so I can test and check the leads to ignition switch.
Also if any one as WIS does it show a test procedure to follow inorder to determine why coils are not firing.
Also is their a test procedure to check the ECU?
I had a lincoln town with a similar problem but only affected 3 cylinders and traced it back to a faulty computer as the computer sends the pulse signal to the ignition coils to fire up.
Also im finding lots of spliced wiring extra fuses installed seems like the previous mechanic really hacked at this vehicle.

 

SO today I tested the CPS and I'm getting about 3 volts from it.
I tested it again but from the computer side to be sure the wiring is ok and yes I still get 3 volts going to computer.
Tested short to ground none all ok.
Im leaning towards a bad computer but still need a test procedure for the ECU.
Any help with this is greatly appreaciated

 

Droopy, have you read chapter 12 of the diagnostic manual: "engine does not start"? --> http://www.benzworld.org/forums/w163-m-class/1416644-useful-w163-documents-8.html#post5432251

Please describe the history of your starting problems.

Like how long ago was the first time you had long-crank-no-start? Has it started before on the 2nd or 3rd attempt? How often does it happen? Why did you replace the CKP sensor a year ago? Were you having starting problems then?

 

The first time was the exact same thing about a year ago.
Crank no start, tested fuel pressure ok.
Tested ignition coils no ground pulse, ordered from NAPA a week later replaced with crank sensor from NAPA and it started right up.
Ran great for several months and now the same problem is happening again crank no start.
basically i need to find out why the ignion coils are not getting pulse signal from the computer? This what I need to know. Can anyone help
Basic problem that I know Im having is no spark on all cylinders.

 

The key word here is "Napa". That only tells us where you bough it, not what you bought. Supply the link to what you bought at Napa.

Without the CKP Sensor working properly, there will be no ground signal from the ECM to the coils.

 

Yes I understand that now after it happened again whic lead me to buy an OEM Mercedes-Benz Crankshaft Position sensor and its still doing the same thing. Crank no start with no ground signal pulse to all ignition coils. Which was the same problem as before.

 

It is possible that the OEM sensor is faulty. It can happen.....

 

Yes very possible but I'm getting good resistance and voltage from sensor.
If someone could provide me with the actual specifications on the resistance and voltage thats suppose to come from the sensor then I will test to be sure.

 

Droopy you are trying to be too scientific......
Scan the car. Faulty CKP will give you a code.
Or ask a friend who owns an ML to replace your sensor with his for diagnostic purposes. It will take you only 20min......... After which if your car starts you can return your new "faulty" CKP to the supplier.....

 

Yes sorry I do tend to dig deep as to cause of issues but in this manner or way I learn and I will be that much more prepaired for the next issue since I will have a better understanding of how things work and measure up.

I tested the crank sensor directly in vehicle with it cranking and I got 3v
then I plugged harness back in and followed wiring back to computer solid green and green with white stripe tested from computer and again 3v at cranking.

Ive done this test before on a lincoln and found the computer faulty but it was onlt to three cylinders not all which leads me to believe it might be something else or just a weird bad computer.
The ML needs lots of maintenance work so if I have to buy a computer Im just going to write it off. Which is the reason Im being so detailed.

If WIS doesnt provide test instructions then thats cool but I would like to know or see what they say about testing a computer. I know you need good ground to it and power but Im not sure what wires are to do what which is why im asking.

Any further guidance is greatly appreciated.:thumbsup:

 

What I meant was, have you been stabbing wires repeatedly to measure these voltages? Every time you do this, you break one or more copper strands which increases the wire's resistance.

Start on page 23/1 of this manual for tests on the ECM --> http://www.benzworld.org/forums/w163-m-class/1416644-useful-w163-documents-8.html#post5432251 However you don't really need to test it because it is the last component to go bad.

What have you done to fix the multiple misfires? The ECM will selectively switch off a misfiring cylinder - if you have 4 of them the engine won't run.

 

LOL, i'm definetly not the tech to stab at wires I made a couple of wire testers to prevent piercing into the harness. So i test from the connectors.
I have all ignition coils dead with no ground pulse. I didnt know the computer cuts out power to the coils which is great to know and thanks for that but leaves me even more clueless as to the problem but I will review the site you provided and continue on from that.
As to the ECM being the last to test I dont know what else in the vehicle will cause the computer to cut off ground power to the coils.
I will rescan the vehicle and see what comes up as last time I cleared all faults in hope that would spur something up.

 

Droopy, in your first post, which was in Jan., you said that you read the codes and there were misfires and random misfire codes present, but you never posted them.

Then in a later post you posted "C" & "B" codes which have nothing to do with the starting of the vehicle.

Erase all of those C & B codes first.

Where are these misfire codes that you claim were present? Read the codes again and post them.

In post #7 I asked if you had a scanner that can read RPM's, but you never answered.

Has the truck been laid up since Jan. or is this an intermittent problem?

I can supply you with a test for the CKP, but these questions must be answered first.

 

SOrry the scanner I used was a cheap Autel code reader only.
Here is what I got in 08 jan 14
P0353 - cylinder 5 misfire
P0302 - ctlinder 2 misfire
P0303 - cylinder 3 misfire
P0305 - cylinder 5 misfire
P0302 - cylinder 2 misfire
P0306 - cylinder 6 misfire
P0300 - random misfire

WIth new Autel DS708
I got several fault codes throught the vehicle but the ones I noted where the ones I thought would be related to the current problem
Here are the codes with new scanner in 08mar14
B1040* - CAN communication fault to ECM
B1086 - CAN BUS communication fault to AAM
C1038 - ECM not identified or incorrect
C1012 - Battery voltage too high
C1210 - Differential lock switch (dont know why I noted this one)