Fisz

Hello,
I have some strange problem with my w204. Sometimes when I try to start the engine, the starter will turn only once (instead of normal 3-4 to fire up the engine), and it not start, when I turn off ignition, and try to start again - it works.
But today when I turned off the engine (after short drive), the electricity was totally lost (I mean nothing worked - radio, elv lock, lights etc). After about 1 minute the electricity automagically came back.

I've connected my Xentry SD, but no errors there. Any guess where to start searching the fault?

Plutoe

I think you have a faulty ignition module.

Fisz

Hm... strange, I never thought, that faulty ignition module will "blackout" the electricity for a while. But thanks. I'll contact my MB workshop to resolve the issue.

PS. Ignition module is integrated with ELV lock? Or it's a separate module?

Fisz

I've made a movie of it (very blurry, sorry for that) - it happened twice in the same moment. When I wanted to start the engine electricity was lost for a while. Additionally engine light came up on dashboard, and it displays "fuel reserve" but I have 3/4 of fuel (you can see the arrow is going up before 1st start).
It looks bad for me, i'd bet that it's faulty sam module...

https://www.youtube.com/watch?v=M3A7...ature=youtu.be

IGB

Not sure why people will default to the most expensive problem....

It could be a crankshaft position sensor. Or possibly a bad thermostat as both of those parts are checked by ECU as you start the ignition starting process.


It is a separate module.

IGB

Not likely....

I can say with 98% certainty that it is neither Electronic Ignition Switch (EIS), nor an Electronic Steering Lock (ESL)... The reason I make this conclusion is that I can hear ESL unlocking @00:07 in that video. Once that gets unlocked, ECU has already confirmed its the right key and has authorized the starting cycle to proceed.

Based on the loss of voltage as well as the quirky fuel gauge display, it could be a weak battery as well...

Good luck!

Russell Ormerod

That's a power supply issue!
Check that your battery terminals are properly secure and tight.
After that have battery tested.

Fisz

Car is in workshop at the moment, waiting for repair, but before this I've checked the battery terminals, and they were tight. I also checked the engine error on Xentry and it was something like this (translated from PL, so it probably won't have the exact name as english xentry): "203A Check N10/1kM element (motor relay terminal 87)".

Russell Ormerod

That would be relay M in the front sam, that powers the engine ecu.
Probably a secondary issue related to your main supply issue.
You a long way away in Poland! Greetings

hasard

My w204 won't crank. It looks like there is an electric problem. The error I get from the diagnosis took is: