SL 350 - Failed to start - Crank Position Sensor?

[Marrijon]

Hello. I did my usual 20 mile commute down the M1 to Sheffield today and stopped at Meadowhall for a fill up.

When I went back to the car it failed to start. Not the usual struggling battery sound you hear or the partial turning off the engine......pretty much nothing....although all of the dials were active on the dash.

I got a kind garage employee to cone off the forecourt and bring his jump leads over. Once connected she started immediately.

I switched off the ignition and re-started a further 2 or 3 times before I let him put his leads away and....no problem....started every time.

I don't think this is a battery issue.

Could it be crank position sensor as I had this fault in my previous SL?

If it so, can anyone give an idea of what the UK repair cost should be for this fault from an German auto-independent?

Thanks.

 

[supernoodle]

If it wasn't even cranking that's not the position sensor.

Have a search of the posts from @DSK about no crank.

 

[SL63 Mark]

Bad Earth ?

 

[DSK]

Mine turned out to be a Terminal 87 relay on a W221 S350 bluetec. W221’s seem to be common for relays here and there.

Diagnostics may help but, I’d probably start off with relays on the back of symptoms you describe, starter relay, then any other relays related to engine. The jump leads seem like a coincidence.

I’ve seen the odd other thread of other models having the random all the lights, no crank, no start issue being solved with a starter relay. I hope you get it sorted as it’s a right pita especially as it’s behinds to get worse.


Sent from my iPhone using Tapatalk

 

[Blobcat]

I'd call in at Prestige Motor Engineers in Ossett (Mercedes specialists) and ask their advice / costs.
I've used them a few times and very happy with their service

 

[-raj-]

Doesn't sound like the crank position sensor but for the sake of £20 its worth throwing in a new Bosch sensor