Hello everyone!

This is my first post on this forum, I've been a Mercedes owner and lurked here for nearly half a decade now but this issue has presented itself difficult to rectify on my own.
I recently came into a purchase of a 2006 C230 sedan (w203.052) with 74,820 original miles in a No Crank No Start condition with an intention to fix and sell the car. M272 V6 engine.

The key upon insertion turns all the way to Position 3 (crank), spring recoil and all, and when left in Position 2 (On), I hear the fuel pump hum.
The car does not start when cranked to Position 3. All you hear is a soft click from the engine bay, but no attempt at cranking.

I charged the battery, checked every fuse, and tested every relay in both SAMs, all checked out fine, including the Engine Management, Starter relays and Fuse No. 52.

I installed a new starter since I had one on hand, cleaned the spark plugs and checked the continuity of each ignition coil, things seem to check out.
I fixed the intake manifold runner issue as the M272 engines are known to have, and reinstalled it. The shrader valve on the fuel rod showed ample psi.

When I connected 12v directly to the starter through a jumper wire, and turned the key to Position 2, the car started right up and idled normally.
I was able to drive it around the neighborhood without any issues whatsoever. When I turn it off, I can not restart the car by the key, but only through a 12v direct jump to the starter.
I then traced the wires running from the starter to the EIS, according to the Benz WIS schematic, through the front SAM and all circuits were properly connected and showed continuity.

I can start the car by jumping terminals 87 and 30 on the starter relay socket, as per a recommendation from another user (MBtech1098) on this thread here: https://mbworld.org/forums/c-class-w...-no-start.html which has proven to be useful to move the car, but not enough to fully get it to sell-ability. That is currently the only method I can start the car with.

I don't think my EIS is fried as I can still turn the key to crank, it's just not receiving the signal to actually crank the engine unless I send 12v through the relay socket. If it is failed, I have a replacement part but I would need to get it cloned or coded to match my VIN.



Please help a lowly automotive student. I thank each and every one of you for your replies in advance.

 

Why would you willingly buy a w203 with no crank condition are eis+ecu+key plug and play kits available for your vehicle on ebay , probably cheaper than repairing this

 

Well you have done a pretty good job of testing the circuit. Remember the eis only sends a CAN message to the engine ecu and the engine ecu actually triggers the starter relay. Also the engine ecu will only trigger the relay if it gets the message via CAN from the gearbox ecu (if its an auto) that the car is in P or N.

 

Thank you for your reply.

I purchased with the intention to sell it, preferably keeping it as stock as possible, which turns me off the idea of a push button start. I don't mind putting in the money for a major dealer repair such as an EIS clone, but there's no excuse for an otherwise immaculate Mercedes with less than 75,000 miles to not be running.

Will you please link an example of an "eis+ecu+key plug and play kit"? Thank you.

 

Thank you for your reply.

Yes the car is an automatic transmission, I was having difficulty locating the plug near the transmission ecu (tcm?) that is supposed to send that said signal. Any tips for locating it? I'll try my best to find it in WIS as well when I get the chance. In your experience, what would your next step be? Do you suggest an ECU rebuild or replacement? I understand that's another piece that must be vin-coded, correct?

Thank you.

 

Hi, i've not found the exact kit for your model, but ive seen eis+key being sold https://www.ebay.com/itm/2005-Merced...-/131566109095

but its probably not plug and play, i dont know for sure, i just assumed. heres another kit from england which includes more parts https://www.ebay.co.uk/itm/MERCEDES-...4383.l4275.c10

I have no idea why the instrument cluster is included... maybe thats required also? and is still not plug and play?
*like everything with mercedes, i bet its not plug and play . $entry / $star diagno$is time!

 

Hello everyone.

Replacing the ECU, EIS, IC, and ESL seems a bit counter-productive, since these modules all match with the car's low mileage, and the low mileage is a grand reason of why I purchased the car in the first place. Thank you for the suggestion, I would be open to this as a last-resort, but being so close to starting the car normally with the key, that would be a different direction of problem solving.

Upon further inspection I crawled under the transmission and checked the plug underneath the shield held by the inverted Torx screw and blew some electronic cleaner on both male and female connectors. Nothing seemed out of the ordinary, there was no oil buildup on the plug or anything of the sort. I'll cross reference with the circuit diagram on WIS and check the connections with the multimeter.