I have a 2003 c240 Its starts runs 3 seconds an dies

Asked by Mar 09, 2017 at 08:27 AM about the 2003 Mercedes-Benz C-Class C 240 Wagon

Question type: Maintenance & Repair

My 2003 c240 runs a few seconds and dies...Will run forever by spraying
ether into the air cleaner...I have replaced the fuel filter...I have not tested the
fuel pressure but presume it is low...I can hear the fuel pump run when i turn
on the key...is there anything else besides a fuel pump that could be causing
this problem? thanks in advance

17 Answers

73,655

It is possible that the fuel injectors or the fuel regulator could be leaking. Doing a fuel pressure test, and a bleed down test will show this. But if you have low fuel pressure, the fuel pump would need to be replaced first. If the problem persist then do a fuel pressure bleed down test.

Iam going to grab a fuel pressure tester today...No doubt i have low pressure...I did read there was a fuel pressure switch, located above the rear tire somewhere?...Should also mention I have replaced the throttle body and maff...I just checked and there are no obd2 codes on my scanner..

73,655

Actual fuel pressure issues don't show up pin pointing to the actual fuel delivery problems, but do show up on some other codes. And the problems usually relate to something that is faulty for those codes.

update... I ran a fuel pressure test and it checked out ok...After removing the gauge the car fired right up and idled on its own...Although when i depress the pedal I have no engine rev, it just stalls....Put the scanner back on and got codes 0123 and 0101 tps and maff i believe...I tried to do the pedal reset and nothing ...thanks for any input

73,655

Ok, your also going to want to check the wires at the plugin to the Throttle Positioning Sensor and they like to break under the insulation at the plugin...P0123 MERCEDES-BENZ - Throttle/Petal Position Sensor/Switch A Circuit High Input...Possible causes; Faulty throttle position sensor, Throttle position sensor harness is open or shorted, Throttle position sensor circuit poor electrical connection......P0101 MERCEDES-BENZ - Mass or Volume Air Flow Circuit Range/Performance Problem...Possible causes; Faulty mass air flow sensor, Intake air leaks, Dirty mass air flow sensor, Dirty mass air filter, Mass air flow sensor harness is open or shorted, Mass air flow sensor circuit poor electrical connection...Before replacing the mass air flow sensor, try replacing the air filter and cleaning the air flow sensor with low compress air or mass air flow sensor cleaner. Reset code and drive vehicle. If the code comes back, it may be necessary to replaced the mass air flow sensor.

Well looks like iam being sidetracked on the fuel delivery problem.. Now when i try and start the car the cluster lights up but the engine does not turn over..When i turn the key it clicks once...The battery is good....I found the paper of the fuse diagram but it doesnt tell me, where the starter relay is...iam not sure if its with the fuses under the hood or if its in the fuses in the trunk...A little annoyed that I cannot find and information on how to identify the relays....any help would be appreiciated

73,655

There are wiring, and fuse box information on line. I'm not that familiar with Mercedes set-up but a lot of vehicles will have a fuse box on the passenger side right kick panel. Usually one on the drivers side and under the hood.

Yes i have found the 3 fuse boxes,,, drivers side hood, driver side dash and drivers side rear trunk...But have searched online looking for the location of the starter relay, with no luck....Thanks for your help

73,655

The battery may be low on charge now.

Yes the battery is low after sitting overnight...good ole interstate, not sure why but interstate batteries are terrible nowdays...ill have to put this on hold a few days as the weather here has turned cold and i cannot get the car into the shop...Till next week ...thanks for your time

73,655

Ok, and yea, Interstate Batteries use to be good until they started making the plates inside thinner. Years ago I had one last 11 years. And it is cold here also, expecting -2° tonight, but going to camp for the weekend. May do some snowmobiling.

Update on the 2003 c240....I put a new rural king battery in it and it now starts up...the interstate after 2 long years just wouldnt hold a charge :-(... Any way the car idles poorly and i have no pedal, just stalls when you give it gas...Still freezing cold here will get back on it this weekend...

73,655

You got me on the edge of my seat...lol, until then...

was 50 this weekend so...I changed the crank sensor camshaft sensor and pedal assembly...Nothing..It did start doing the previous problem again ...run 3 seconds and die..The fellow i bought the car from said he tried a new throttle body and maf from autozone with no luck...Well I unplugged the maf now the car runs idles and accelerates, but has a slight hesitation when you first start moving... Iam hoping the aftermarket maf he purchased was generic and wouldnt function properly....Mean while ive noticed the new battery discharges at during night, so i unplugged the seat sensors and will see if it holds charge tonight....lol

Last update for the c240....Its fixed!! I puchased a new bosch maf for 130$ and the car runs as It should... I cleared the codes , drove about 40-50 miles no check engine light no hesitation...As for the seat control units, the battery seems to spin the car right over this morning...I unplugged both sides so ill narrow it down now to which side is bad...Thanks for your comments

73,655

Good to hear. If you have trouble finding that parasitic draw here is a video on how to find it... www.youtube.com/watch?v=QRso1A0VScw

Thanks ill check it out...

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