My 2001 w210 will not crank. Battery appears OK and all other electircal systems work. All fuses look OK and I swapped all like-kind relays.

The starter got stuck yesterday and kept cranking after the engine started. I shut the engine off and restarted. All was fine. Went to restart later and not it will not crank.

My first thought was that it was a starter solenoid issue. Not being able to replace just the solenoid, I replaced the starter. Yes, I should have bench tested the starter but ..... Engine still will not crank.

Anyone have a suggestion how to proceed?

 

K40 Relay in the control module box (passenger side under the engine bay) remove the 4 screws & you will see a little black box with some fuses, wires & one black relay, change the relay by a new one

Fabio Daniel

 

Fabio

You were dead lugnuts on! Mucho Thanks.

When I pulled the back cover off of the K40 relay it was obvious where a component had failed and fried the circuit board.

The part number is A 000 540 00 72 and was in stock at MB with a retail price of $111.63. BTW this appears to be the part number for most/all W210s. It took all of 10 minutes to replace.

Here's a pic of the bad part. Note the copper section which got hot, burned off the green top layer, lifted off the board, and finally melted the copper in half.

 

hope it help you bro! let me know any news

at your order my friend!

PD: Bro i see some white sulfite marks in the green board, check the proper fitment of the box module cover to not entered any water.. hot modules without proper closed box produce some evaporation & appers this marks burning relays, modules, etc. check too inside the EGS module if you not have any trans oil inside, some cases oil inside the EGS burns the relay box

Fabio Daniel

 

Yeah, I saw the sulfate(?) stains too and thought it might be from water intrusion but when I looked at the bottom of the plastic cover there were no water stains or deposits.

Thanks again!

 

All good my friend

Fabio Daniel

 

I have a similar situation. After a long drive and have the car shut off, and when I tried to start it back on 15 minutes later, there's this long crank and the car will not start. My tech told me it's the Crankshaft Position Sensor. So could my case be the relay too?

 

Nope because your car is cranking. The relay problem is this thread prevents the car from cranking. The Crankshaft position sensor will prevent the engine from starting. Common problem on the w210 and on Chrysler Jeep vehicles

 

1+

Crank + no start = Position sensor or fuel pump (most common)

No crank, no start, no nothing = Battery, relay, starter (most common)

Fabio Daniel

 

I have the same issue, car will
not crank and the K40 relay looks good
Battery is im good conditions