Ron in SC

I got around to getting a new CPS. It came a Hella box with MB part number on the box of 003-153-2828, I believe that is the correct number. The sensor itself has the number and manufactor name ground off, it only says made in Germany.

I test the new one with an ohm meter and it measured 664 ohm applied heat with heat gun and it slowly went to 725 ohm.

When I tested my old one it measured 1148 ohm applied heat and it quickly went to 1250 ohm.

Are the ohm readings supposed to be different for the new CPS?

WienerWater

Yes, the reading for the new one is in perfect range, and is exactly how to test it, heat it up slowly, but not too much, since you can also damage it if you go above normal engine temps. Another thing you can do, once the old one is heated, is to give it a gentle tap, along the length of the sensor, and also watch the reading. The reading will just bounce around way out of range, where the new one should just bounce a bit (I wouldn't tap or hit a new one, just because).
Just make sure the new one will fit the connector you have in your ML, since a dealer insisted I needed the updated one, and when I had it sent to me, the connector was a bit different shaped inside, and can't be used.You need the one that fits proper, nothing else.

Ron in SC

Thanks for getting back to me. I've posted on a few MB webforums. I did not want to put the new one in until I was sure it was ok to have such different ohm readings. The new one does have the proper connection I was just concerned about putting it in and getting a check engine light and then having to go to the dealer to have it re initialized or whatever it's called.

As I said when I used my heat gun the old one got more resistance much much faster than the new one. My old one has not effected how the car starts or runs I just thought with the problems people have with the CPS sensors I should just replace it anyway. My ML 320 1999 has 113K miles on it.

Edited:
I did what you said about heating and tapping on them. I tap gently with my finger. On the old one the reading jumped around a bit but it did not lose continuity. On the new one the reading did not jump around at all.

WienerWater

My '99 ML has 57K miles on it, and was told that you should consider it a maintenance item, at 80K miles, if it hasn't been done yet, since it is a common issue. The CEL may take a couple of start cycles, to clear the code, or you can do it with a scan tool (or a dealer/ any decent shop) it takes 2 minutes at tops.I would think a decent shop of any kind would just clear it for free.
I had mine fail, within about 2 days after changing my MAS sensor, so it really had me confused "what the hell now"?? LOL It's just fate I guess, anyway, just install it, tighten in carefully, and all should be fine.

Ron in SC

I never got the check engine light so I should not have it when I put the new one in. I say that because I took the old one out in August to test it and just put it back in the vehicle with no problem. I think you one get the light if the CPS fails when the engine is running.

WienerWater

That's right...needs to run to send the code, otherwise not.

Ron in SC

Installed new CPS this morning. Everything works fine. I'll just keep that old one as a spare should the new one fail.

Must say I was surprised by the difference between the ohm readings on the two different CPS.

55fanatic

what is a CPS unit?

Ron in SC

Crankshaft position sensor.

MIKE_ML430

i think im having a cps problem. i start my suv and sometimes it takes more then one crank to start and after it starts and i go somewear and it sits for a wihle it won't start. and now today it stalled it never did that befor. i would drive it and when it got warmed up it won't start againg till it set for 30-40 min. am i right is it the cps?

where is the cps locate? and can i change it my self? and what tools do i need?