CLK320 hard start when hot, and CEL with P0341 error code

[MarkCorrigansBoiler]

Hello,

I usually use my car for shortish journeys but did a long journey of 2.5 hours recently. After stopping for petrol after about an hour, my 2003 W209 CLK320 (petrol) threw a Check Engine Light but otherwise ran fine. After stopping again later, the car would crank over fine, but would not start, after a few more minutes, I tried it again and it started and drove fine. The same thing just occurred on the drive home (after stopping after a couple of hour and trying to restart, it would crank, but not start. After a few minutes, it started and drove fine.)

I pulled the codes and the only one stored was a P0341 which indicates "Camshaft Position Sensor A Circuit Range/Performance Bank 1 or Single Sensor"

I've done a whole bunch of searching and reading and I'm a bit confused. Sue to the similarities in name, a lot of people seem to be confusing the Cam Position Sensor and the Crank Position sensor.

Do the symptoms I describe sound like the Cam (as indicated by the code) or the Crank sensor is at fault? The Internet seems to suggest the Crank being a more common fault and matches my symptoms, but the P0341 code suggests the Cam sensor.

Any help appreciated.

I'm hoping for the Cam as it looks like an easier part to replace on the M112 Thanks.

 

[alexanderfoti]

Symptoms sound like classic crank position sensor.

Crank sensor can be diagnosed by looking at rpm on diag whilst cranking. If nothing shows up issue is crank sensor.

 

[ajlsl600]

As above. Some crank sensors won't stop a motor. But will prevent a restart and throw ann eml eventually there will be no restart. Buy sensor. Or test as above.

 

[MarkCorrigansBoiler]

Thanks. I've ordered the cam sensor as it looks like an easy swap and is only £35ish for the Bosch one. If that doesn't work, I'll probably get the local indy to do the crank sensor as it looks a bit of a ball-ache.

I'll update the thread either way.

The problem with diagnosing the crank sensor using the diagnostics is that I can't recreate the no-start condition without doing a 2 hour drive first. I'll maybe keep the OBD scanner in the car anyway in case it happens when I'm out and about.

 

[MarkCorrigansBoiler]

The cam sensor finally showed up and I've replaced it, I love an excuse to use my 1/4" torque wrench. The new sensor design looks a little different and the new (Bosch) one looks ever so slightly shorter than the existing (MB branded) one. Even so, the car starts and runs fine and after I cleared the codes, nothing new has been logged. A long journey will be the real test, but I won't be doing one of those for a couple of weeks.

Incidentally, I figured out the data logging capability of my Launch OBD Reader and could see RPMs on cranking. But I assume if the non-starting problem only occurs when hot, this is when I would need to look at the data?

Thanks again for your help thus far.

 

[MarkCorrigansBoiler]

I just thought I should update this thread. The issue was the Cam sensor as indicated by the code. Replacing it fixed the issue and it's been fine ever since.