evilsaint

So, the C32 has pretty much been sitting since I bought my 1 Series (heresy, I know), and I'm trying to get her ready for sale, especially since I've got someone with cash who wants to check her out. Despite the brand new battery though - less than three months - and it sitting at a healthy 12.65 volts, the car won't crank at all.

Key in, turn, and not even a click. The diag menu works, all the accessories work as well, but not even a semblance of a click, nor the fuel pump running in advance of starting the car. The radiator fan does spin up to an obnoxious speed and then slow down after a minute or two, and I can't contact the ECU to pull MB or OBD codes (three different readers), but other than that, I've got nothing. Any ideas?

evilsaint

Update: I tried to jump it with a less electrically complicated car with a brand new battery, but nothing doing - the key slots in, turns to position 1 or 2, but nothing happens when you turn to crank.

It has at least one other CEL so I don't know if there are new ones, because the ECU can't be contacted, even though the OBD2 port is showing connected and giving power. Not only can't the "OBD ECU" be contacted, but neither can any of the MB-specific ECUs in any of three separate apps that work on a 2003 W203 that a friend of mine has. Two separate code readers as well unable to read anything/contact any the regular ECU. No new error codes on the dash.

Dead SAM or something? Fried ECU? I've never heard the radiator fan go full throttle like it's doing now, but it seems like a failsafe of some sort. Could it be a fuse/relay that tried to pop but didn't go all the way or something? I've got no idea where to start...

Dollos

Have you tried checking all the fuses in the front and back sam?

But to me it seems like when you changed the battery you might have popped something.

Lenin

Was the car outside during the winter? Is there is a chance that moisture got into the ECU? Take out the ECU and make sure everything is dry, then put it back and try again. Also, 12.6 V is low. You need 13, close to 14 V to call it healthy.

Velociabstract

This is a frequent occurrence (on Crossfires) and usually caused by cracked solder joints in the RCM. Pull it out and inspect it with a good magnifying glass. I couldn't see a visual problem with mine but had all the symptoms. I purchased a new one from Ebay (Rockauto has them), installed it and problem fixed.

Les

evilsaint

What's the RCM?

evilsaint

Isn't that the voltage for when it's running, though? Either way, I'll put the trickle charger back on it for longer - maybe it's still just not charged back up. I replaced the battery ~3 months ago, but I never drove the car to get the new battery charged by the alternator or anything, so it was sitting through some questionable weather.

Velociabstract

RCM = Relay Control Module. Sometime I forget the W203 is a lot different from the R170 so your module may be called something different. When our cars won't start, the lights and accessories work, not even a click when the key is turned it's almost always a fault in the module. It's in the fuse box in the engine compartment and has fuses plugged into it.
http://bayhas.com/mercedes/w203/cont...ne_contmod.htm

Good luck,

Les

evilsaint

Ah yeah, I know where that is. I replaced the relay for the secondary air injection pump in there semi-recently, so maybe I screwed something up - I didn't do a whole lot of driving after putting that in and then going to pass emissions. Anyway, thanks for the info!