2006 ML500
Weirdest thing happened today. I parked the car yesterday afternoon and everything was normal. Today, I noticed that I had no power at all, nothing was working; even the key wouldn't turn the ignition; signs attributed to dead battery. I checked the battery with a voltmeter, it had 12.3 V! I used the jumper anyway to start the car, and it did. While engine was running, I noticed that none of buttons on the steering wheel were working. The radio worked so was everything else except the said buttons. I hooked up the code reader and as I randomly selected to lock the rear left door, which has a faulty lock, the engine shut off instead! Everything went dead all of a sudden. I turned the engine on and off a few times and everything seemed fine except the buttons on the steering wheel. The buttons started working after a few times of turning engine on and off.
Not sure if this can happen again while I'm driving.
By looking around the forum I'm guessing the rear sam to be the culprit.
Please guide me through this problem.

 

Anything less than 12.4 V is a sign of a bad battery.

 

But should it shut off the engine? Also it shows 13.6 V when engine is running, and it starts without any hesitation repeatedly.

 

let us know what you find out i have weird electrical problems as well little different than yours but suspect front or rear SAM

 

The electronics are sensitive to voltage, yes. I'd try charging the battery and see if it takes a charge to at least 12.6. If it stays below 12.4, change it before looking at anything more complicated. The 13.6 means your alternator is working, but if the battery won't come up above 12.4 when the engine's off, it's topping out at 50% charge or less. That will cause all kinds of errors.

 

Sorry for pressing on. But how do you explain engine shut off?

 

There are a lot of electronics that are sensitive to low voltage. Let say the ECU isn't getting enough current to operate properly. Anything can happen.

Maybe you have a bad SAM. But if you're battery won't charge to a resting voltage of 12.4 or greater, it's something to look into first.

 

Gentlemen, battery voltage when a veh. is idle should be 12.7 volts. And at 12.4v it should not prevent starting nor should it not shut the eng. down, unless there is an alternator problem.

Where did you jump start the truck, at the main battery or from under the hood?

Here is a PDF on the failing steering wheel buttons.

 

Two things: OP was at 12.3V, not 12.4. In terms of diagnosing a battery that's a big difference. Second, the chart you attached is for flooded-cell batteries. I'm not sure when MB switched to AGM, but they have slightly higher voltage. Instead of 12.6, they should show 12.7-12.9 when resting.

 

Regardless of the battery he has, the readings should not have shut down the engine.

 

From under the hood. Last year I had a bad battery, by the time I changed the battery I had to jump start the car a few times. Once the battery was replaced, everything was ok. That was more than a 6 months ago. Until couple of days ago that this happened.

 

What was the make of the battery you bought a year ago?

Then remove both cables on the main battery, GROUND first, then POSITIVE second. Make sure there is no corrosion, replace POSITIVE first and GROUND last. Then see if the problem recurs.

 

Motormaster ELU49/L5/H8
I'll do the test and let you know
Follow up: Did the battery exercise and scanned to see what I get. For rear SAM there was no code. For the front SAM there was no Checked Fault Codes, but about quite a few, more than 40 Unchecked Fault Codes that would not erase. Some to do with bad stop lights that are working on Substitutes. But a lot of them to do with shorts in circuits and the like. Don't know if they got anything to do with the problem. Here are some of the codes I had on Front SAM

Just wondering what are the differences between Checked and Unchecked Fault Codes.

 

Just wondering what are the differences between Checked and Unchecked Fault Codes. You must read your owner's manual.

Did you check for codes in ALL modules?

Post the codes that cannot be deleted. No photos of the code reader. List them as follows

1.
2.
3.

 

These are the fault codes for Front SAM that cannot be deleted:

Vehicle : /scan/BENZ/
Test Path : Benz, Automatic selection, Automatic selection, Control Units, Body, SAM-F-Signal acquisition and
actuation module front , Read codes, Checked fault codes, Unchecked fault codes, All fault codes
Read codes
9001 Component E1e1 (Left high beam) or the lead has short circuit. Not defined
9002 Component E1e1 (Left high beam) is faulty or the lead has open circuit. Not defined
9003 Component E2e1 (Right high beam) or the lead has short circuit. Not defined
9004 Component E2e1 (Right high beam) is faulty or the lead has open circuit. Not defined
9005 Component E1e2 (Left low beam) or the lead has short circuit. Not defined
9006 Component E1e2 (Left low beam) is faulty or the lead has open circuit. Not defined
9007 Component E2e2 (Right low beam) or the lead has short circuit. Not defined
9008 Component E2e2 (Right low beam) is faulty or the lead has open circuit. Not defined
9009 Component E5/1 (Left fog lamp) or the lead has short circuit. Not defined
900A Component E5/1 (Left fog lamp) is faulty or the lead has open circuit. Not defined
900B Component E5/2 (Right fog lamp) or the lead has short circuit. Not defined
900C Component E5/2 (Right fog lamp) is faulty or the lead has open circuit. Not defined
9011 The component or the signal line to the component E1e5 (Left turn signal lamp) has Open circuit or Short
circuit to ground. Not defined
9012 The component or the signal line to the component E2e5 (Right turn signal lamp) has Open circuit or Short
circuit to ground. Not defined
9013 The component or the signal line to the component Switch illumination has Open circuit or Short circuit to
ground. Not defined
9014 Component Footwell lighting or the lead has short circuit. Not defined
9015 The lead to component Footwell lighting has Open circuit. Not defined
9016 The component or the signal line to the component M5/1 (Windshield washer fluid pump) has Open circuit or
Short circuit to ground. Not checked
9019 Component R2/2 (Left washer nozzle heater) or R2/3 (Right washer nozzle heater) or the feed line has a short
circuit Not checked
901C Component R13/1 (Left front seat heated cushion) or component R13/2 (Left front backrest heated cushion) is
overloaded or has a short circuit. Not checked
901D Component R13/1 (Left front seat heated cushion) or component R13/2 (Left front backrest heated cushion)
has an open circuit or is defective. Not checked
901E The power supply line to component R13/1 (Left front seat heated cushion) or R13/2 (Left front backrest
heated cushion) has Short circuit to positive. Not defined
901F Component R13/3 (Right front seat heated cushion) or component R13/4 (Right front backrest heated cushion)
is overloaded or has a short circuit. Not checked
9020 Component R13/3 (Right front seat heated cushion) or component R13/4 (Right front backrest heated cushion)
has an open circuit or is defective. Not checked
9021 The power supply line to component R13/3 (Right front seat heated cushion) or R13/4 (Right front backrest
heated cushion) has Short circuit to positive. Not defined
9022 Wake-up line from control unit N10 (Front SAM control unit) to control unit N51 (AIRmatic with ADS control
module) has Short circuit to ground. Not defined
9029 Component M6/1 (wiper motor) is stiff or blocked. / Voltage supply to component M6/1 (wiper motor) Not
defined
902A The component or the signal line to the component F58kB (Wiper ON/OFF relay) has Short circuit to ground.
Not defined
902B The component or the signal line to the component F58kB (Wiper ON/OFF relay) has Short circuit to positive.
Not defined
902C Component F58kB (Wiper ON/OFF relay) is defective or missing, or the feed line has Open circuit. Not
defined
902D The component or the signal line to the component F58kA (Wiper level 1/2 relay) has Short circuit to ground.
Not defined
902E The component or the signal line to the component F58kA (Wiper level 1/2 relay) has Short circuit to positive.
Not defined
902F Component F58kA (Wiper level 1/2 relay) is defective or missing, or the feed line has Open circuit. Not
defined
9030 The component or the signal line to the component F58kF (Fanfare horn relay) has Short circuit to ground.
Not defined
9031 The component or the signal line to the component F58kF (Fanfare horn relay) has Short circuit to positive.
Not checked
9032 Component F58kF (Fanfare horn relay) is defective or missing, or the feed line has Open circuit. Not defined
903B Components F58kD (Engine circuit 87 relay) and F58kH (Circuit 15 relay) are defective or not installed, or the
feed line has Open circuit. Not defined
903C Component F58kH (Circuit 15 relay) is defective or missing, or the feed line has Open circuit. Not defined
905D Component F58kH (Circuit 15 relay) is defective or missing, or the feed line has Open circuit. Not defined
9060 M14/8 (CL left rear door motor) : Short circuit to ground Not defined
9063 Component S11 (Brake fluid indicator switch) is defective. Not defined
9064 S21/4 (Right rear power window switch) : The switch is sticking. Not defined
9065 S21/3 (Left rear power window switch) : The switch is sticking. Not defined
9066 The right rear power window relay is defective (the contact is stuck in the switched state or the relay fails to
energize). Not defined
9067 The left rear power window relay is defective (the contact is stuck in the switched state or the relay fails to
energize). Not defined
9068 M10/6 (Right rear power window motor) : The right rear Hall sensor does not supply a signal. Not defined
9069 The left rear Hall sensor M10/5 (Left rear power window motor) does not supply a signal. Not defined
906A M14/8 (CL left rear door motor) : Open circuit in wiring Not defined

2019-09-23 11:37:16

 

There are 50 or so codes which can only mean that there has been rain water intrusion or your veh. was a flooder.

 

Not since 2010 when I bought this car. Unaware of what happened before then. But I can't see any sign of water intrusion. Would you please give me a couple of codes that are your suspects.

 

Remove everything including the gray mat in the spare tire compartment and see if there is or has been any water intrusion. The rear SAM is located there along with the tailgate module and pump are located.

 

Thanks Major. As I mentioned on my post, the fault codes I sent are from Front SAM. Rear SAM had no fault codes. Are you still suspicious of the Rear SAM?

 

Sorry, but if all these codes cannot be deleted, then there must be something catastrophic with the front SAM.

Front seat is #3.

 

Please check for codes in the EIS (Electronic Ign. Switch) control module before you remove the front SAM.

Also check fuse #14 in the right side fuse panel.

 

No fault on EIS module. Fuse 14 is good.
Pulled these for Instrument Cluster. Not sure if they have any relevance though!

IC-Instrument cluster , Read codes, IC-Instrument cluster , Read codes,
Checked fault codes, Unchecked fault codes
Read codes
9100 The instrument cluster no longer transmits over the engine CAN databus. Status 'CAN bus OFF' Not defined
9110 The instrument cluster no longer transmits over the interior CAN databus. Not defined
912B Invalid drive authorization data Not defined
912C The main odometer reading is incorrect (too low). Not defined
913C 'Reset' pushbutton jamming. Not defined
9134 Fuel tank sensor tight installation recognition: The signal from the fuel tank sensor 1 is not plausible. Not
defined
9135 Fuel tank sensor tight installation recognition: The signal from the fuel tank sensor 2 is not plausible. Not
defined

 

When are you going to look at the front SAM?

At this time the IC codes are a result of the front SAM codes.

 

It'll be tomorrow sometime. What should I be looking for?

 

Water, loose connectors, battery corrosion and anything else that looks foreign.