George Sercombe

Hi, My 2007 Clk350 problem started last weekend when my wife decided to take the MB out for the second time on Saturday. She came to me and said the car won't start. I tried and it turned over fine but keeps turning over when the FOB is rotated from the start to run key position. Tried different things to determine if it was a safety-security issue and found nothing. Sunday morning I sprayed CRC Electronics cleaner into EIS and blew out with canned dry air. This worked and we took the MB to local car show. Returned to the MB and it started the stalled out when put into drive. Repeated the cleaning procedure but could not start the car. Towed home and two local dealership estimate 1250 to 1500 dollars to replace the EIS that includes 5 hours of labor. Do you think that my problem could be anything other than the EIS?
Maybe the CPS?
Thank You for your advise - George Sercombe


George.......your CLK is a W209, which unfortunately, had a lot of teething issues with both the 350 engine and 722.9xx transmission.

You'll find more help here: https://mbworld.org/forums/clk-class-w209-43/


After the initial post I detected a P0335 diagnosis code. Replaced the CPS and everything was fine for the first trip. Stopped the CLK and then it was back to the same - Car turns over but will not Start. No diagnosis codes.

Any suggestions W209 gang?

Rudeney

Where did yo get the CPS? You need a genuine MBZ or Bosch. And unfortunately, eBay and Amazon sell a lot of fakes.

George Sercombe

The CPS I purchase and installed is from Bech/Arnley. I will go to MB tomorrow morning and redo this part replacement. No diagnosis code this time. Thanks for your advise.

George Sercombe

Hi, I replaced the Beck/Arney CPS with the MBZ. No change. Then check for fuel pressure at the fuel rail and the want any. Took back seat out and no bolts at the fuel pump. Brown wire to fuel pump no volts. I checked all fuses engine compartment, drivers side and trunk fuse panels. Don't know where the relay is. Your help is greatly appreciated.
Also the battery box drain was clogged, up 1/2 on the battery. Electric leaf blower cleared the drain with a good amount water flowed out.

Rudeney

So is the car not starting at all now, even when it is cooled down? And to clarify, you have no pressure at the fuel rail? In that case,a fuel pump issue is a possibility. Check the fuses and relay first. It;s fue #4 on the panel in the trunk, and relay "A". See this diagram:

http://benzbits.com/w209/FuseBoxRear.pdf

George Sercombe

The test of the #4 fuse and the A relay were fine (12 volts). Then found 12 volts at the drivers side fuel pump (black and green wire). Conclusion is to replace the left and right fuel sending (drivers side) unit and the fuel filter/level unit. Total cost is $620 for both units and an updated wiring harness. Sounds a bit expensive to me. Any other suggestions for a less expensive seller? Your help is greatly appreciated. George

Rudeney

So is there any pressure on the fuel system? I think before spending that much on a new pump, I'd make sure that is the problem.

George Sercombe

Thanks for the good advise. I will go back over the diagnosis of the fuel pump failure before spending $620. I do appear to be very scattered addressing this problem. Thanks again for your assistance.

George Sercombe

Checked the fuel pump electrical system this afternoon the Sunday surprise occurred and the CLK started up. One extra step taken was to blow dry air into the ignition switch. Drove the car home and spent a couple hours cleaning and reassembled the back seat and engine compartment. Will test drive this week and will communicate any developments. Thank for your assistance in this two week experience. George

George Sercombe

Monday the CLK started up fine and after the second stop would not start. Waited a bit of time and it did start but on the next stop of the car would not start. 20 or more attempts to start and nothing. Waited 15 minutes and it started. Brought it home and this morning started up fine and one stop everything fine, second stop return to the car and it started and then puttered out. No fuel pressure at the Schrader valve on the fuel rail. Before testing for fuel pressure I cooled off the ECU with a running hose and it went from ambulant temperature of 97 down to 84 and the ECU cooled dramatically. My situation is mapping to VSPBTOWN with a 2007 CLK550 (I have a 350) but cooling the ECU does not work all the time. Sunday and Monday it was helpful to cool the ECU but not today.
I do not hear the fuel pump with the back left (drivers side) seat out and the cover off - even when starting fine. This is likely due to my age and hearing loss.
Is it time to bring the car to a repair shop with the correct MBZ diagnostic software to manually turn the fuel pump on?
Or should I reorder the fuel pump unit and the filter/fuel level unit and replace both now to correct the intermittant problem?
Thanks, George

Rudeney

I would definitely get he fuel pump checked.

George Sercombe

Thank You Rudeney. I appreciate your support and advice. George

George Sercombe

I replaced the fuel pump and the fuel sending units on the CLK350 and all starting problems were resolved. Drove the car for short trip and problems arose. A p0106 diagnosis error was generated. And I replaced the mass airflow sensor soon after that. Problem resolved. Took the car out for test drive and the climate control system started to go on and off redirect the air to the defrost then to the floor. Recently replaced the dash panel for the
climate control with a used one. Hard to believe that the same problem is reoccurring. I will post this issue on the forum. Thanks

George Sercombe

Thank you