clb0099

Hey all,

so over the last couple of weeks I been tracking down why my car randomly doesn’t start. I have scanned the car over 20 times and was getting random codes. Cleared them and started off with a clean slate waiting to see what codes will come back. I also have to state that I have batteries, and start which were all replaced under 2 years. The common code is consumer shutoff and consumer battery which is the battery in the trunk. When I check the voltage to the rear battery is was extremely low. The front starter battery volt is 12..my car is 07 am I at a loss now cause I my car didn’t start this morning but when I came home after work the car started right up. What I noticed also is that as soon as I get in the car and turn the key to accessories I get message on my command screen they says low battery and that my command system will close in 3 mins.. my interior lights don’t come on unless I press the buttons. Any one can shed some light on my issues? My car 2007 s550. Is it the bcm?

Jaap

This.
Forget everything else and start here.
Something is draining your rear battery.
Fix that first.

BOTUS

leave the rear connected to a powerful modern trickle charger and see if the car keeps behaving ?

when I first got the car in 2014 the original 7 year old rear battery kept it alive for 20 mins - the two replacements never managed that long (even when brand knew and fully charged) - after 4 1/2 years into its 5 year warranty this Yuasa one tested as worn out and its free replacement is equally naff - its the same OEM 25kg AGM spec

everything today is budget crap aimed to last 3 years before the world ends - but its really mostly toast at 18 months

.

clb0099

Rear battery is Battery is fully charged and it has the same way where it wants to start but never does. I can only think it’s the maybe the fuel pump failed?

chassis

Resistance caused by corrosion. Corrosion caused by water. Water coming in from above e.g. sunroof, trunk gasket, door gasket etc. Look for water intrusion. Open all SAMs and fuse boxes and pull all fuses. Look at all ground points and ground straps in the engine bay. Each...and...every...one...of...them.

Disconnect all aftermarket electrical items (dashcam, alarm, etc.).

clb0099

Would I get a fault code for failing fuel pump? Being that my car is 07 my guess is no since there is no fuel pump module in my.

OldManAndHisCar

In my instance, the drain on the battery was the car being driven 2 mi to the clinic, 2 mi home from the clinic day after day after day....it never got a chance to recharge.

justchangeoil63

If there is something that is voltage-related, no matter what, get a new battery ASAP! I had a brand new battery from Mercedes and after 2 months it was acting odd, just got a new one and fixed the issue. You can have defective batteries, maybe after 1 day, 2 months, or even just 1 year, it happens. I'm sure you know these cars are very VERY sensitive to voltage, I mean if it's off by even the slightest amount tons of components will "Fail". Please please please try a new battery first before you spend money on parts! Always best to rule out the battery in situations like these, honestly try all the batteries. Also, to the best of your ability, check for corrosion on the wires related to the batteries and just anything you can see.

Good luck!!!

BOTUS

got a mate with a CL500 (CL550 to USA guys) - his is early 2009 with large single front battery

he gets a new battery on mobilo breakdown all the time - tests as dead inside a year, so they fit yet another one - never been anything wrong with any of the 5 he's had in the last 3 years - the real tip is to just drive the car

clb0099

Ok, update .. so I do drive the car continuously it’s my daily hence why it has 195k miles. I sourced the issue and it’s very common w221 issue that I fixed once before. The front sam has front electrical center base module # 221-545-1601 that sits on top of the sam itself and the part that holds the fuses and relays. We’ll relay “c” on the part was tripping continuously. That relay has direct connection to the ecm. About 2 years ago I replaced this electrical center base module with a used one from eBay .. probably a mistake but I did it. This past February I decided to buy a brand new one for $408.00 from Mercedes of Laredo. I never installed it. The base comes with all the relays and fuses installed. Needless to say after installing the new part the car starts right and no issues. I rescanned the car and all the errors I was getting are gone. This part I listed is an updated part from what was in my car when first built. The batteries were also tested by 2 different places (starter & rear battery) both were perfectly fine. Thanks everyone who helped me track down this issue.

clb0099

Ok, update .. so I do drive the car continuously it’s my daily hence why it has 195k miles. I sourced the issue and it’s very common w221 issue that I fixed once before. The front sam has front electrical center base module # 221-545-1601 that sits on top of the sam itself and the part that holds the fuses and relays. We’ll relay “c” on the part was tripping continuously. That relay has direct connection to the ecm. About 2 years ago I replaced this electrical center base module with a used one from eBay .. probably a mistake but I did it. This past February I decided to buy a brand new one for $408.00 from Mercedes of Laredo. I never installed it. The base comes with all the relays and fuses installed. Needless to say after installing the new part the car starts right and no issues. I rescanned the car and all the errors I was getting are gone. This part I listed is an updated part from what was in my car when first built. The batteries were also tested by 2 different places (starter & rear battery) both were fine… while I am typing this I am laughing as I drove the car to the store shut it off and went to start and no go. Went to the back fuse box and removed the fuel pump relay and swapped it for a new one and after several tried the car started.. I am at a loss.. is the fuel pump or is the rear electrical base module that went to **** to now and it’s making proper connections? Also rescanned the car while isn’t in as starting and no codes lol .. the codes I got before never reappeared either.

clb0099

So after my last post I ended up replacing the fuel pump and it started right up good, right? Lol well I shut the car off and tried to start it hour later and to my surprise it didn’t start lol . I rescanned it and got different codes. Then I tested my rear battery and starter battery. I checked for how much charge was on my starter battery after trying to start the car once. It was at 49% .. needless to say I need to replace the starter battery as it failed.. thankfully it’s under warranty for another year so Monday morning I will be picking it up. To confirm that it was the starter battery issue I took jumper cables and connected one side to my Mercedes gl and the other side to the starter battery terminals that were disconnected from the battery and the car started right up.

JohnLane

OP.... Re-read your posts. “It won’t start.”

Does it crank on the starter motor?

“Cranks, no start” is very different from “Get in, apply brake, press button and does not crank.”

Codes are one small piece of the puzzle.

clb0099

John,


cranks won’t start .. my apologies


QUOTE=JohnLane;9004498]OP.... Re-read your posts. “It won’t start.”

Does it crank on the starter motor?

“Cranks, no start” is very different from “Get in, apply brake, press button and does not crank.”

Codes are one small piece of the puzzle.[/QUOTE]

JohnLane

Cranks won’t start.

How old is crankshaft position sensor?

Common failure. Often presents with no codes.

clb0099

that was replaced when this first started happening

QUOTE=JohnLane;9004574]Cranks won’t start.

How old is crankshaft position sensor?

Common failure. Often presents with no codes.[/QUOTE]

BOTUS

do USA guys need to molest the brake pedal to start their 221's ?

wot a waste of space..... european cars are just normal - no beeps or bong and no faffing pressing pedals, we just have a normal car and if I want to take the key out that's just fine too

JohnLane

Be thankful! Our .gov overlords are bound and determined to keep us from killing ourselves and others. Not that it helps but it makes plenty work for the manner of twit that needs to control such things. You’d think it would be enough to require the dumb thing to be in Park or Neutral to crank.

OldManAndHisCar

Odd note...our new Sprinter 3500/Airstream Interstate will stert with out a foot on the brake.

clb0099

So after all this I found a post on another forum which is identical to the errors I got originally when this problem started and it looks like the fix was a new ecm ..

JohnLane

Well here’s hoping that will be the end of it. Get with Peter about coding it.