Complete electronics failure on the CL

[Maff]

Driving home today and ‘Battery Charge Low, visit workshop’ appeared on display. Followed by, 'Switch on engine or COMAND will shut down in 2 minutes' on COMAND screen!

3 minutes later, ESP failed, BAS, ABS, Tire monitor, Coolant error and loads of other messages popped up in sequence.

Then the Speedo stopped working, then power steering went, then car went into limp mode.

Followed by major engine misfire, then the electronic accelerator pedal went. So car was on tick over in second gear with very rough idle.

Pulled (rolled) over, stopped engine, battery dead completely. Couldn’t open boot (to get to battery) as no electrics, so called Mobilo out.

After 30 mins there was enough power to open the boot, and I managed to get a jump start off a mate. All went well, carried on home, but two miles up the road the above happened again, this time stopping on a busy dual carriageway.

Jumped again, and managed to get home. Mobilo come round and it looks like the alternator has gone, or a belt is slipping.

Battery seems fine, takes charge but all the electronics use up it’s power pretty quickly, thus killing the engine (electronic fuel injection to blame?!)

Lets see what the dealers say on Monday, when it’s delivered to them on a flatbed…..


More trouble......

 

[GrahamC230K]

Sorry to hear that Maff. Such a top of the line prestige car, but still not immune to such fundamental failures...and from your list there is a lot of gizmos that rely on that battery.

Ask them why it doesnt have a backup alternator

 

[glojo]

In the good old days you would expect to see a simple warning light indicating the battery was not being charged? Have we lost that?

As you say, alternator, loose belt or perhaps defective battery.

With our E-class they simply put in a new battery, and touch wood that solved the problem.

Good luck getting it sorted,
John

 

[Guy]

Before the days of such complex electronics, we had a similar problem on our 300TE estate - no warning lights, but died at the side of the road. 15 mins later, battery recovered enough to restart and travel a few miles.

Problem was the alternator - producing some charge, but not enough, so battery slowly being drained. MB's explanation for the lack of warning light was that the 'failure' was insufficiently great to bring the warning light on...

 

[andy_k]

sounds very much like the alternator, you can almost guarantee it's a 10 pence piece of carbon that's broken down.

In the "good old days" when we could actually mend the cars we drive we used to be able to buy new brushes for alternators

Good luck getting it fixed

Andy

 

[fuzzer]

so that 12v Iron you were using wasnt a good idea then ?

 

[del320]

CL55 AMG bites man's bum!

"One serial car buyer's newest toy came with a few surprises..."
"Fully loaded...packed with toys...Every option box ticked...PlayStation ...delimited...ECU remapped..."

You don't ever have premonitions, Maff?

Get rid of it!!!

BTW, how did you ever manage to steer it to the side of the road?
The immobiliser threw a wobbly on my previous 300CE-24 some years ago. Everything went out like a light and I was about standing on the seat wrestling the brute to a halt at the roadside

Amazing the trust we place on 5amp fuses

 

[Maff]

LOL!

The steering was heavy, but not bad enough that it couldn't be steered. I had to use two hands instead of the normal one hand!

 

[PJH]

I remember a story on the BBC Watchdog a couple of years ago that was just like this.
An owner had his car die on him in middle lane of M25 during rush hour.
MB couldn't find the fault.

 

[No1vic]

Alternator failure

I had a similiar experience last week, driving my Mercedes Actros articulated lorry. Coming off the motorway and slowing down, recharge battery warning message came on as the engine revs dropped, I then lost the gear selection, followed by engine stalling which then left me with no power assisted steering or brakes. Very difficult to control without the assistance and a fully loaded trailer, luckily no one was on the motorway junction island which I couldn't stop for at the give way marker! I was left partly blocking the slip road and traffic island. Not a lot of warning of the failure, it seems the alternator was just about putting enough power out to keep it running on the motorway while discharging the batteries but as soon as the engine revs dropped it was all over with so many systems dependant on the power supply.

 

[Maff]

It seems we're all driving electric cars these days without realising it!

 

[glojo]

followed by engine stalling which then left me with no power assisted steering or brakes. Very difficult to control without the assistance and a fully loaded trailer,

Amazing!!!!!!

I thought that by law, if trailers lost their air pressure the brakes locked on? Luckily you managed to stop without any serious incident, but the compensatory liabilty that might well fall onto Mercedes-Benz beggars believe.

I would be very interested to know when this safety feature was withdrawn?

Take care,
John

 

[pammy]

sorry to hear of your prob's Matt - not what you want to see on such a car. But I had to chuckle on Top Gear last night when JC was forced to cover his week of woe with his Ford GT - hilarious

 

[scotth_uk]

Any chance it could be ECU remap related?

 

[Maff]

I thought that, but its been OK up until now, and would be strange for the ECU to throw a spanner in the works at this late stage.

Will see what MB say, no doubt they will inform me as well as the alternator Control Unit X, Y and Z also need replacing with a two week wait from Germany

 

[glojo]

Will see what MB say, no doubt they will inform me as well as the alternator Control Unit X, Y and Z also need replacing with a two week wait from Germany

Hopefully you will have a very nice courtesy car?

John

 

[saorbust]

If units need replacing and the vehicle is off road (or VOR in MB terms) the parts should be with the dealer in less than 48 hours. Two weeks is the normal delivery window for non essential items.

Hope they sort the car soon.

 

[Satch]

Remeber the "BIG" recall at the end of March?

Well one of the issues there was failures of Altenator control units and that was said to be a temperature related problem.

Just a thought....

 

[Maff]

Dealer just confirmed it was the alternator, however we will see if this was the real cause when the new one arrives tomorrow...

 

[Maff]

Remeber the "BIG" recall at the end of March?

Well one of the issues there was failures of Altenator control units and that was said to be a temperature related problem.

Just a thought....

Spot on Satch, this was exactly what had failed. They replaced this and all was fine. Alternator itself was also fine.

Car's back now and all is good