My 2004 E320 has been experincing stalling problem lately. It stalled mainly when it comes to the stop or slowing down to the turn. I also noiced that the gas pedel does not have a great response like it used to be sometimes (stepping of the gas and do not see the rpm increase and the car move slowly). But everytime it stalled, it would start right back up. I have already changed out the CPS because back then it has a starting problem. The code read P0335 (CPS a circuit malfuction) and P0442 EVAP Emission Control system (small). I have not really looking into it because now it is the wife's car and she does not drive it that often.
So I do not know that I need another CPS or a fuel pump. I have already replaced the fuel filter back about 30k miles ago.
Thank you
Tom

 

Hi Tom,
I had a similar problem last month with my 2004 E320. When my 2004 E320 started experiencing stalling problems, it came up suddenly while I was driving it to the body shop. It just stopped in traffic as I was coming to a stop. After about 5 minutes, it started back up and I finished my drive to the shop.
It did the same thing to them, so they replaced the CPS.
The car runs like new today.
Just my personal experience, but I'd say it is still your CPS. Take it back to the place that did the work and have them re-do it. If you did it yourself, go back and carefully check every step of the job...it might have been loose, or misaligned? Good luck!
Jim

 

New doesn't = Good

A new cps can be defective. Perhaps that's why they sell so many.

 

You have code P0335, which is an error in the crankshaft position sensor CIRCUIT. That does not necessarily mean the sensor itself. Take the connector off the new one and look at the connector pins to see if they are dirty or damaged. You could get a spray can of electric connector cleaner from Autozone and give that a try.

Also take a look at the whole cable for physical damage. Is it routing close to a magnetic source, like a plug wire? Is it well seated at both ends, so far as you can tell?

Do you get the same code with each sensor installed? If so, that points to it maybe not being the CPS itself and more likely the wiring for the CPS, but I agree that a new part is not necessarily a good part.

 

Once again correct. CPS means the signal is not triggering the engine to fire. Now the reason could be the part OR assoicated wiring.

My diesel truck would not start and had a code for Injector drive module a $800 part. I found the real cause of no start was the relay to the IDM had failed in the PDM. The cost of the relay was $5.00 at Autozone, and that was 3 years ago. So $5.00 vs $800 + tow was a big savings. You have to consider the system to include the cps part. But you might still have a bad new part.

 

Thank you very much for all replies. I will check soon.

 

I have a 2004 E320, having similar issue. It stalled mainly when it comes to the stop or light after driving for about 10 miles or on the highway. Or it won't start after coming out from grocery shop. My mechanic can't find error code, he has no problem when test driving. Only once not able to start. Been to the shop couple times and both times, mechanic could not tell me what's wrong. Is it the CPS or the MAF? please help. Thank you.

 

The CPS is so cheap and easy to replace, might as well do it. MAF is more expensive. However you can try unplugging it and see what happens. Might get a check engine light however.

 

The CPS sucks in our cars. When mine failed, I bought a cheap replacement from Advanced Auto, because it was in stock, and that CPS failed as well in a couple days. Then I bought a Bosch CPS and my car has ran perfect ever since. The part is not expensive either way. It is true it is an "easy" repair once you remove the sensor. The first time it took me hours to dig it out, and it wasn't until the perfect combination of socket wrench and flexible extension that I could pull the sensor. Just wanted to mention this because if you do all that work to unplug the sensor to test it you might was well replace it. It is going to fail eventually anyways.