Fault B48/2 and icarsoft MBII diagnosis .

Botus

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S500/2010/500
Turned on the ignition, small red srs light came on then disappeared after a few seconds, started her up & the main centre display stayed clear of any large red SRS visit workshop display. So far so good, took her for 3 test drives this afternoon & no SRS faults have reappeared (touch wood) !

mine came and went over a year and seemed happier with a fully charged battery (where it ran off and hid for 6 months straight), when I did change it the terminals and connection were like new... a new sensor for £40 and its been fault free for 3 years
 

Vindiesel

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S211.208 evo E220 cdi 2008 / S203 C220 cdi 2003 {sadly sold on}
Yep Botus, I doubt I've seen the end of this fault this easily.

Funny enough about a week ago my battery was low on charge, she barely turned over on a particularly cold morning. That has possibly triggered the borderline sensor B48/2 DTC.

The car has intermittent use, I'll keep her fully charged over the winter period & plug in the solar charger to keep her topped up between smart charges, hopefully this will keep her happier for a while.

I'll pick up a new Mercedes/bosch sensor shortly so it's to hand if the current one starts playing up again.
 
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Your Mercedes
W211 E280 Avantgarde cdi Estate 2006 Facelift 3 litre V6 OM 642.920.
Had a warning message come up 2 or 3 times over the last few months (the warning was for the SRS system ) each time it went out after a few minutes driving and never returned .
I bourght an Icarsoft MB2 last week and just had the chance to use it today . The fault showed ...
Fault in connection with component B48/2 , passenger side frontal acceleration sensor , OR there is a cable fault .
I searched the forum for fault B48/2 and found that it is a sensor that is under the headlight which is easily accessed by removing the front section under tray .
There were other posts that suggested it must be the same part number and same make for the new part ? Also a mention of being careful with the description of drivers side of passenger side because of MB's left hand drive heritage .
Firstly I think I will just clean up the electrical contacts for each sensor , I'm half wondering that each time the warning light has come on it's been after jetwashing and/or heavy rain ?
So in conclusion , the MB2 has been a good investment (even an idiot can use it :geek: ) . The forum search facility on previous posts and eBay for putting the part number in and getting a picture of the sensor has been under an hours work .
Next decent day I'll have a look underneath .
I have just had exactly the same come up on my 1996 E280 cdi S211. Did it solve the problem? We have had heavy rain and I have jetwashed the car too! What was the part number that you obtained?
 
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Wighty

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W211/E320cdi/2009 and CLK200k 2009
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I have just had exactly the same come up on my 1996 E280 cdi S211. Did it solve the problem? We have had heavy rain and I have jetwashed the car too! What was the part number that you obtained?
I ended up changing the main car battery and it has never come back since 2018 . MB’s hate low voltage on the batteries ?
 
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W211 E280 Avantgarde cdi Estate 2006 Facelift 3 litre V6 OM 642.920.
My fault showed up after I had replaced the battery and due to lockdown the car was not used for some time. I used my powerful charger and then got the fault next time I fired up the car. I have cleared the fault but it comes back as it is eeing that the problem still exists. I need to get at the sensor.
 
Joined
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Berriew, Powys, Wales
Your Mercedes
W211 E280 Avantgarde cdi Estate 2006 Facelift 3 litre V6 OM 642.920.
Found them with the help of Haynes , either side of the front rad on the vertical metal work and very well hidden , a lot smaller than I thought as well, looks like the air filter boxes and pipes need to come out to access the two 10mm bolts . It has taken 2 hours to find them .
The half salmon collection tin I have below my turbo intake orange seal had a load of oil in it , so it's either new seals , or a new pcv valve or I pull my finger out and fit my oil catch can which is in the garage . All of the above sounds like a warm day project .
I can't feel my hands at the moment :(
My E280 Estate has had this problem with the oil dripping down onto the turbo controller. My independant MB engineer suggested a tampon! Pretty good that - Mercedes Benz needs tampons! I had taken off the old controller and pulled it apart. it was dry inside. The issue I think is that the oil gets to the contacts externally and may change the resistance/short the connector. It cause my engine to cut out for a millisecond or so, every half second. This happened when on full power. It is a severe form of transmission shunt and needs to be avoided as the loads involved must be enormous. I replaced the turbo and controller and the problem went away. I think that it is an issue with the back pressure being too great and the system shut the system down momentarily. My independant said that the acceleration was very impressive but the boost pressure was too high. He was not sure why and we replaced the turbo/controller on that basis. The problem has gone away. I have my suspicions that the previous owner had the car chipped.
 

clk-chris

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2005 CLK 320
My fault showed up after I had replaced the battery and due to lockdown the car was not used for some time. I used my powerful charger and then got the fault next time I fired up the car. I have cleared the fault but it comes back as it is eeing that the problem still exists. I need to get at the sensor.
Did you end up replacing the sensor and did that fix the problem? I have the same error code (thank you iCarsoft), and the history on mine is similar (low battery charge, charging the battery then SRS error code). I recharged my battery, left it 12 hours and checked with with a Foxwell scanner and it checks out good, so I think my battery is good. I also swapped the drivers side and passenger side sensor, but the code did not switch sides. I was thinking of checking the voltage at the sensor connector with a Power Probe, but because it is part of the SRS, I was a little hesitant to do that. In the past, I jumped the battery a few times, and each time that resulted in a fried coil pack.. Now I will only disconnect the battery to charge and will not allow it to be jumped anymore. The low battery seems to result in problems so many times. I just need to get this SRS figured out, hopefully it doesn't need a new control module!
 
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Wighty

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Did you end up replacing the sensor and did that fix the problem? I have the same error code (thank you iCarsoft), and the history on mine is similar (low battery charge, charging the battery then SRS error code). I recharged my battery, left it 12 hours and checked with with a Foxwell scanner and it checks out good, so I think my battery is good. I also swapped the drivers side and passenger side sensor, but the code did not switch sides. I was thinking of checking the voltage at the sensor connector with a Power Probe, but because it is part of the SRS, I was a little hesitant to do that. In the past, I jumped the battery a few times, and each time that resulted in a fried coil pack.. Now I will only disconnect the battery to charge and will not allow it to be jumped anymore. The low battery seems to result in problems so many times. I just need to get this SRS figured out, hopefully it doesn't need a new control module!
How old is the battery buddy , date stamp probably on the terminal . When you say the battery is good , what volts Is it showing ?
 

clk-chris

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2005 CLK 320
How old is the battery buddy , date stamp probably on the terminal . When you say the battery is good , what volts Is it showing ?
About 3 years. I charged it for about 5 hours, left it completely disconnected for about 14 hours, and at that point the scanner was showing 12.5V, and was measuring 836CCA (it is rated for 900). I wanted to think it was the battery, but I think it is ok (I would be very happy though if it was as easy as a battery :) ). I checked for a parasitic draw, when I immediately connect the battery it reads about 3 amps (yes, 3) for about 10-20 seconds, then drops to .5 for a few, then down to .1-.14 for about 20-30 minutes, then stays at .01. I'm currently looking into that initial 3 amp draw, as that sounds too high, even for just 10 seconds (there is a very loud zap). Now that I'm typing, I wonder if maybe the alternator has a short (it is remanufactured, and does this strange thing where after it reaches operating temperature, its voltage drops from 14.2, slowly to 13.5, and the car shakes when the dropping starts...I'll try to look more at the alternator).
Just when the SRS B48/2 came on, it mimicked the problem of sitting, recharging, SRS light came on. And just like some of the previous posts the car had been sitting for a while, but recharging the battery didn't seem to fix the problem. I do suspect the low charge and trying to start it did have something to do with initially triggering the SRS problem, now I need to fix it!!
 

clk-chris

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Just a quick update. I tested the alternator with a multimeter. It appears to check out ok. I had .01-.02V for positive alternator post to positive battery post .04V for negative battery post to alternator case, and the AC ripple current was a little strange, but I think that was because I forgot the car wasn't warmed up. Without warming up, it was around 30V, but once the alternator did the strange shake thing at operating temperature, it immediately went to 0, even with reving the engine and turning every accessory on it remained at 0. I tried clearing the SRS when the AC voltage disappeared, but the SRS came right back (I thought maybe the AC voltage was in essence blocking the code from clearing, but no luck.. first time I thought of that theory). I did notice when the doors close, or when the windows fully open or close and the button remains pressed, it almost sounds like a slight engine stall, so maybe the alternator is not fully working.
I think at this point, I just need to determine if the sensor is getting power. I found a complete SRS wiring diagram, but the 48/2 and 48/1 sensor doesn't seem to be in it! My car is a 209, but I highly suspect this aspect is the same for the E.
 

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