Crank sensor , trying to figure out if it's gone or not. The ohms on multimeter is coming in at .73 . Am I correct in saying it should be much higher? Tested it with the ignition on and tested it completely unplugged and reading is the same

 

A good sensor would measure a resistance of 600 - 1200 ohms at 20 degrees centigrade.

 

So if I just had the ignition on and the car was cold would the reading not be correct, I need to test in when warm?

 

Our engines use the 2 wire magnetic sensor method, where the rotating teeth on a ring gear, induce voltage pulses in the CPS coil, that provides input to the engine control module, which determines ignition system timing, so that he proper air and fuel mixture will ignite at the proper moment.

A faulty sensor can easily cause:

- Intermittent starting
- Engine misfires
- Engine stalls
- Engine hesitations and/or vibrations

Typically, but not always, a faulty CPS will throw a CEL and/or P0335 DTC.

Enclosed below is section 9, of the MB "Ignition System Test" procedure, detailing how dealerships would test the CPS.



Note: The signal and voltage tests in section 9.0 require either the engine being cranked or running, which requires an expensive factory test cable and 128 pin breakout box, which is not required to perform the resistance measurement as detailed in section 9.1 .

The vast amount of CPS failures, first begin as a soft failure, where:

- A warm engine will crank but not restart, until the engine cools down.
-The engine completely shuts off, usually when slowing down or stopped in traffic, but will restart after a few attempts.

Given the number of forum CPS failure threads, it's a wear and tear item, which probably should be replaced as preventive maintenance.

The Bosch OEM CPS only costs around $25 and is an easy DIY replacement (e.g. took me less than 10 minutes on my M112 engine).

The only PITA was access to the CPS on the bell housing. To avoid scraped hands or an aching back, I found using a 1/4" ratchet wrench with a very long extension and E8 torx socket worked well. If the socket isn't magnetized, add some bearing grease to prevent losing the single fastening screw. Also, during production, the W208 used 2 different CPS harness connectors (e.g. only difference being that there will be 1 or 2 locking tabs to squeeze to remove the CPS connector).

 

Ok new crank sensor gone in and STILL misfire on cylinder four and a broken heart here. not sure what else there is. Injector, spark plugs and lead, coil pack, all new vacuum hoses, MAF sensor and now crank sensor and will it misfires on four