View Full Version : CMP (cam position sensor) issue

09-16-2013, 02:09 PM
Have made a read out of codes from Can data modules and got failure code
For CPM sensor in module fuel injection and ezl ignition module. I have replaced the sensor so i dont think there is any problems with is. I think the
coaxial cable is bad. I contacted MB and asked for this cable and they
said that the part can not be purchased. The cable is included if i buy a complete engine harness. I have already replaced the engine harness by making own cables. I can not buy a complete engine harness when i only need the CPM sensor wire. Anybody there knows if it can be bought separately or how i can solve the problem ? Maybe i can make a new cable if i have the correct sockets for both ends of the cable.

09-16-2013, 02:26 PM

I am not an expert on this, but a good info to add on such questions is the model year of your car and the VIN.

Welcome to the board BTW. :-)


09-16-2013, 02:31 PM
My car is MB 500E -93. Engine 119.974

09-16-2013, 03:20 PM
The cam position sensor cable is integrated into the engine wiring harness. AFAIK, it is not available separately. However if the insulation is not damaged and the cable tests out OK with an ohm meter, the cable is not likely to be the problem.

What is the exact code (or codes) from the EZL?

Have you checked the air gap on the sensor per the factory manual and adjusted the shims as necessary?


09-16-2013, 11:57 PM
Thank´s gsxr for yor quick reply.

Error codes from modules. Readout made with home made LED equipment:

Fuel injection: Pin 6, error 8, CMP sensor signal, open, short circuit
EZL ignition: Pin 17, error 6, CMP sensor defective

I have difficulties to measure the resistance from the connector on the sensor side. The resistance is not stable and it is har to get proper connection. I have measured the value on the sensor and it seem to be okay according to the service manual so i believe still that i have play in the cable. Today i will buzzer the cable to state the problem. Anyway if it is the cable, how can i fix it if the cable is not avaliable, any good ideas is appreciated

09-17-2013, 08:51 AM
If the cable is bad, you'll need to replace the harness - I don't know of any other alternative. A new harness is ~$650 USD here in USA. Sometimes good used ones (late date code) show up for less. On a budget, a 400E/E420 harness may work, good used ones show up at times for under $200 USD.


09-24-2013, 05:59 AM
I have found the solution. I have bought the cable with the CMP socket. Art no: 1295402281. The cable is not shown in the MB 500E parts catalogue but this cable is is used in other MB cars so it is avaliable as a repair kit without the connector to the other side of the cable.

09-24-2013, 06:56 AM
Thanks for the update -- this is useful information.

Can you post a photo of this cable?


09-24-2013, 09:43 AM
I'd like to see the other end of the cable... not sure how you can splice coax, unless it comes with the proper connector on the other end too...?


09-24-2013, 01:08 PM
Picture of the cable enclosed.


09-24-2013, 01:13 PM
Thank you!