Mercedes Repair Questions? Ask a Mechanic for Answers ASAP
These faults didn't happen before the wash, correct?
Ok, did you find any moisture in the trunk?
When you replaced the PSE?
Any signs of corrosion on the PSE connector?
With the lights turning on and off, it seems as if one of the SAM modules got wet
Ok, did you check the front fuse boxes under the hood
The left and right front sam modules reside under the fuse box covers along each fender near the firewall.
So water got in on the passenger side?
Water must have contaminated one of sam modules. It is the only thing that controls the lights.
Are all the lights going on and off or just the front or rear?
If the carpet got damp that means a substantial amount of water got in
There are control units under the carpet along the floorboards
Doesn't matter if you let it dry out, the damage was done
Yes, just sign back on here with your laptop
I don't know how but I know you can get back into the chat somehow.
hi im back
What CAN faults did you have?
None that had a code. I did have a fault in the single wire communicaiton
however i dont have the mercedes can tool, only star diagnosis, epc, star finder, wis...ect
Ok, there probably are many fault codes related to CAN, but you can't read them all unless you have a Star Diagnostic Machine/SDS
ill be back in 5 minutes
I can say with almost 100% certainty that the front sam/fuse and relay module on the driver's side is bad.
The driver's side must have gotten wet too, at least underneath the carpet.
The ABC suspension module is under there and water must have entered through the driver's side fuse box area
The driver's side fuse and relay module also controls all of the lights so that would explain all the lighting issues
I would remove it and disconnect all the electrical connectors, then separate the actual SAM computer from the fuse box and inspect all of those connections for water damage
You may also have to replace the ABC computer located under the driver's side dash but I would first start with the SAM module.
There is no water or dampness under the drivers side carpet
Are you right or left hand drive?
i have removed the accelerator pedal and under dash trim carpets and seat and there isnt a hint of water.
Ok, so the passenger side sam module side got wet
the abs computer is under the drivers side dash rhs and i have unplugged and plugged it back in but still no fix
But the sam module power it up
the passenger side module was dry, i have removed it and inspected all terminals
and if it is sending irregular voltage, it will cause the improper level
there are no fault codes for the any of the sam modules.
is there any otehr way to test the passenger side sam module
Have you checked your battery voltage with the car running?
yes, and i have previously replaced both the starter battery and consumer battery 2 months ago.
I have also cleaned most of the ground points, W3 included.
I know, I just want to see if the alternator isn't overcharging
I have seen alternators put out 15-17 volts which causes all sorts of other problems.
What type of scanner do you have?
You really need a SDS machine to test the passenger front sam
I know you said you didn't have any fault codes for any of the SAM modules but are you sure your scanner is capable of reading all fault codes?
Surely there has to be some faults stored with the lights going on and off, some sort of communication or can faults
You said you had a fault for the CAN being in single wire mode? Some control unit must be taking down the CAN communication
My best guess is the SAM thats on the side of the water
So the left side, correct?
I have the genuine mercedes scanner, we are an independent mercedes workshop
Yes the left side.
Can you communicate with the left side ok?
Have you checked any of the CAN blocks on the left side?
They could have gotten wet and started to corrode.
I have, both the green and brown multiplugs, no sign of corrosion or dampness.
I have also unplugged and plugged back in the central gateway on the rhs
Does your SDS actually make it through a short test or does it freeze up at the right front SAM module?
Have you come across this problem before?
Yes, a lot actually
It makes it through, no exlamation marks just a tick.
It is common for water to get into those fuse boxes
after a car wash
or a heavy rain
It happens a lot
Is it due to the drain on the wheel arch
Right, so water filled up the cowling and spilled into the passenge floor
Not that much really. It was clogged but only a bit of dampness under the carpet
What fault codes do you have in the other control units?
Any in the CGW, or Instrument Cluster, or EIS?
If you do a network interrogation test with the CGW/system diagnosis, does everthing come up on the interior and engine CANs?
I know you found no water entry on the right side, but all of your symptoms points towards a faulty driver's fuse and relay module + fuse box assembly.
I would really just replace that if I didn't find any other water damage under the carpets.
I know you said it didn't get wet but it is the only thing that controls the lights, feeds power to the ABC module.
Drivers side bing the rhs?
The bigger one
The smaller one is the passenger side
It doesn't control the lights
Is there any control unit adaptations, initial startup or actuations in the rh sam that would remedy this
No, the only thing in there is version coding but that wouldn't have just changed on its own.
I have to sign off now, I can continue this chat tomorrow
If you find anything else, just post it here
and I'll reply back tomorrow
Ok, ill talk to you tommorow, what time
Ok, ill post any findings here. Cheers
Well I won't be able to do a full on chat tomorrow so just post a question and I'll reply back
I'll be busy at my dealership tomorrow so I won't have that much time to stay in a chat, I'll just check back here every so often.
These are the event memories of the control modules - front sam, passenger sam, rear sam, instrument cluster and also the can bus interrogation log. The event memories would register several times (ie: No. would be up to 6) and then the event memory would read internal error. Also the event memories registered intermittently as both stored and as current and stored. I hope this helps, as i am in desperate need of a plausible remedy.
Oh and i have also attached the vario roof control module event memory.
Any help would be greatly appreciated and i will re-imburse you for your time and expertise.
Other problems the car has:
-rev counter, petrol gauge and all other needles on instrument cluster innactive then bounce back to life intermittently.
Have you had a chance to check?
Sorry about the wait, I had some unexpected circumstances come up. I noticed no one decided to help you yet so I'll continue to help you work through your problem. I'm just taking a look at the documents now, I'll post some more information in a bit.
Thank You, XXXXX XXXXX awaiting your response. Just for my information however, are where abouts are you located?
Yes I have, I had to do that to get the seat switches to start working again.
If you did mean N32/2 I have disconnected it, performed a quick test and erased fault codes, but am still left with the same list of codes and the same symptoms. Does the front sam control the rear park lights, the vario roof and the ABC module? In Australia the front SAM Module is well over $1000 and I need to be certain this is the fault as opposed to something else on the CAN Bus. Judging by the documents I have given you and keeping in mind most of the event memories switch between "stored" and "current and stored" fault codes is there any vehicle your dealership has had in the past with the same or similar codes?
Thank You, XXXXX XXXXX try this and reply back.
Hello, I have just tried this and my results are as follows.
1 connecter on the passenger side when pulled resulted in the aux fan staying on but the abc and headlights still flashing.
2 more connectors on the passenger side when pulled resulted in the exterior lights staying permanently on even when the headlight switch was off, but the abc still malfunctioning.
1 connecter on the drivers side(RHD) when pulled resulted in the battery light staying on and the headlights staying on but the abc still malfunctioning.
2 connectors on the drivers side when pulled resulted in the exterior lights always on but the abc still malfunctioning.
So in conclusion no plug resulted in the abc being fixed and some resulted in the exterior lights staying on.
What does this mean?
Furthermore, as you said pull out the connectors to see if most of the problems go away, does this mean it will need the drivers side sam plus another control unit?
The theory is, is that one control unit is causing the malfunctions on the CAN bus. So by disconnecting one connector at a time, eventually you will find the control unit that is causing the problem. Since you remove the faulty control unit off of the CAN bus, you are allowing the rest of the CAN to operate normally. Since you removed the faulty control unit from the CAN bus, just about all of the other functions should be restored except the control unit that you unplugged. For example, if you unplugged the ABC module off of the CAN bus and everything else worked except for the ABC, then I would bet the ABC module is faulty and causing all of the problems. If you unplug the ABC connectors and start the car, do the lights work normally?
I just removed the drivers side SAM and re soldered all the circuts. and then reinstalled and removed all the fault codes and the problem is still the same. I have unplugged individual can plugs with the results mentioned in my previous post. Is there anything else you can think of?
Can you actually post an entire short test with all the fault codes of all the modules?
This is the entire 7 page short test performed after the new drivers side sam module was installed and initial start up was performed.
Please reply as soon as possible.
I'm looking at wiring right now. Can you try and unplug the Instrument Cluster and tell me what happens. You could just pull fuse 21 and 22 in the driver's sam but I would feel better if you could unplug the whole cluster.
Ok, I will await your response, please reply soon.
For some reason I was thinking the central gateway was under the driver's side dash but I'm pretty sure on your model it is under the passenger side dash, mounted against the side by the blower motor. I bet you it got wet. I thought you said you checked all the control units in that vicinity but it must have gotten wet, nothing else makes any sense.
The epc states that it is the amplifier. The part under the drivers side says central gateway
Ok, then its the same as in the U.S. The CGW is on the passenger side here in the U.S. which is the right side. Yours is still on the right side then. Are you sure the CGW didn't get wet at all? Even a few drips could have damaged it.
By unplugging it and the problems still being there would this not rule out the cgw?
there was no dampness on the rhs or any water ingress in the drivers side sam or footwell
I'm here, sorry I have been on the phone with a customer from my dealer. . Unplugging the CGW will cause everything to be a mess but if you unplugged it and the ABC stopped adjusting up and down by itself, you might be on to something since the ABC module doesn't need any information from the interior network. Try it and let me know what happens with the ABC.
No, I unplugged it and everything remained the same
*unplugged the cgw
can you disconnect each can block so its isolated and measure the resistance between the 2 pins, it should be around 60 or 120 Ohms. If one of these can blocks terminating resistors is bad, it could also cause all these can malfunctions.
So i unplug each plug from the green and brown can blocks one at a time from both the passenger footwell and drivers foot well and measure the resistance of each plug one at a time with the engine running?
Is 60 the min and 120 the ma reading or can it fluctuate between these 2 numbers but not below 60 or above 120?
No, it should be +/- 2 ohms within that number. Depending on the block, some are at 60 ohms and some are at 120. If you get something like 10 ohms or 200 ohms, then you know you have a problem. I mean, pull all of the wires out of the block and just measure 1 set of 2 pins to get the resistance of the block.
so i pull out all the wires out of one can block and test only one plug to get the resistance of the entire can block and then put them back and continue onto the second can block and so on. Does it matter what order i put the plugs back in each can block?
and is this with the engine running?
No, not with the engine running and yes, pull all of the connectors out of the block, and hook up one test lead to one pin, and the other test lead to the other pin of the block. So you will have the two test leads right next to each other in the same plug housing spot of the block.
The offending plug number is XXXXX
Ok, that must be the main can plug that connects the driver's to the passeger side. I need you to plug that connector back in on the driver's side. Then go to the passenger side can block and start doing the same thing until you find one that allows the ABC to start working. One last thing you should check since I still think water caused all this mess. In the trunk, below the convertible top hydraulic pump is the PSE/Central locking pump that is encased in foam. I need you to remove this pump and check the electrical connectors for corrosion.
The ABC works with plug 102 disconnected which is on the drivers side, I have already replaced the PSE Pump and the boot vacuum element so no water ingress there.
Are you asking me to find the corresponding plug in the passenger side can block? would it be numbered 102?
You checked the PSE pump after you washed the car though right? The plug you pulled on the driver's side(102) is connection between the passenger CAN block. I suggest you plug that 102 back in and move to the passenger side. Now start unplugging the connectors on the passenger side one at a time and then reinserting them. While each plug is out, see if the ABC is working normally. See if you can narrow it down to one plug again. I can tell by your short test that the the (102) connector does not go to a specific module but to the passenger junction block.
I removed plug 122 from the passenger side brown can multiplug and the abc would not work. Plug 122 when inserted back in allows the abc to work, however it still automatically moves up and down. There also there are several plugs that have 122 inscribed. What does this mean?
Furthermore when i unplug this particular 122 plug the auxiliary engine fan stays on.
For the Brown CAN BUS Multiplugs;
-On the drivers side when I unplug plug 102 Lights Correct, ABC Correct
-On the pass side when i unplug plug 102 Lights Faulty , ABC Correct
when i unplug plug 122 Lights Faulty , ABC Does Not Work
On the passenger side - Wire Colours
-Plug 102 - BrownBlack/Brown
-Plug 122 - BrownRed/Brown
Did you get the messages?
Ok, let me just tell you the 122 plug means that goes to regular control units and 102 means it connects the other CAN bridge, the only way to find out which computer one of those 122 plugs goes to is to do a CAN specified/actual configuration test in the central gateway/system diagnosis module while that particular 122 plug is disconnected from the CAN block. Then you can see which module doesn't have communication.
I need you to start disconnecting plugs from the CAN block by the rear SAM. Disconnect one at a time to see if you can get the ABC and lights to work normally again.
Unplug plug 102 - Lights Correct, ABC Correct
Unplug plug 102 - Lights Faulty, ABC Correct (BrBlk/Br)
Unplug plug 122 - Lights Faulty, ABC Does Not Work(BrRd/Br)
Unplug plug 122 - Lights Correct(But Rear Parkers On), ABC Correct(BrBlk/Br)
Unplug Plug 4.1 - Lights Correct, ABC Correct(BrRd/Br)
-Plug 102 - BrownBlack/Brown
-Plug 122 - BrownRed/Brown
Ok, so plug everything back in except the 2 plugs by the rear sam (122 and 4.1.) Perform a quick test and erase all fault codes. Then go into system diagnosis or central gateway and look at the actual values for actual/specified CAN configuration of the Interior CAN and let me know what modules show up "!"
I have included the 'interior CAN checks' with just plug 4.1 unplugged and also the 'interior CAN checks' with both plug 4.1 and 122 unplugged.
Reason is because with plug 4.1 unplugged the lights function correctly and the ABC functions correctly; Whereas when plug 122 is unplugged the the lights work correctly with the exception of the rear parking lights staying on, and the ABC functions correctly.
Also keep in mind the passenger seat has been removed so the SRS light has been triggered.
Ok, try plugging all the connectors back in and then unplug the Audio Gateway/Most Master and see what happens. The AGW is the control unit on the right, The black one in the center is the amplifier.
I disconnected the AGW and the problems seem to have fixed, how did you figure this out based on the results i gave you?