Need help with a 1996 E320 K40 relay
 

Greetings everyone, first time poster here but long time Benz owner.

My neighbor has a 1996 E320 sedan that he has asked for some help with. It seems it has been intermittently and suddenly dieing while driving. No stumbling to a stall, just suddenly no more engine. Attempting to restart the engine would be met with starter but no fire. Then after allowing things to set for a while it would restart. First thing I thought was K40 and CPS. I started at the K40 as it is the easiest to access. First impression is the 40 amp fuse in the F4 position is blown. I opened up the K40 and there is no sign of damaged solder points. I replaced the 40 amp as a long shot and it proceeded to burn it out with in a min of the engine running.

Can anyone tell me if they feel if the K40 is bad it would burn out said fuse, or is it more likely something else upstream, deeper in the electronics is burning it out? Interesting note, the car will start and run with this fuse popped, not sure how long, but I was surprised by this.

Thanks for any and all assistance.

K38 starter relay is something I had to replace,a pink relay.Problem was starter would not operated when underhood temps were high.Dying while driving then starting after cooling sounds like cps.Be sure and buy a hella brand

I agree, symptoms sound cps-like. Though I don't believe a malfunctioning cps would pop the 40 amp fuse, so I am going to continue to follow what is causing that as the issue first.

No problems with the starter, so I don't suspect k38 relay.

Crank position sensor...

J.G.

also had a problem that mercedes could not fix.The plug on the cps was loose

Would a bad CPS blow the 40 amp fuse on the K40?

don't know but I also replaced ignition switch

read at another forum this fix.His dealer found out the computer fan had a short.He disconnected the fan