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I am keen to further understand how amazing chaos can snowball issues across CAN networks: B, C, E1/2.
Such as the solderless MFK Gateway arguing with Instrument Cluster Gateway to display road signs and speedlimit info... makes two busy gateways tied-up unable to transact timely data for others.
The dedicated Bosch Central Gateway hosted in the F-SAM module may very well be the chief troublemaker - Now we have a chance to find out by only resetting it alone!
Today I was helping un-confuse people about battery issues (link) when I got a quick shortcut idea....
What if we just pull the power away from the power controller... reset the crazy N93 gateway ?
We need to know what Fuses # power the CGW Gateway and the F-SAM... I guess N93 + N10/1, right?
CAN modules are allegedly able to be distressed under the radar without any published fault code until is wonky disrupted.
> How is that...?
I am talking about improving the latency performance.
CAN resiliency is built upon retransmits.
When a node can't get no satisfaction, it keeps retrying.
The gateway literally keeps track of each individual outstanding message connections... that queue depth has limits. Limited in size and limited in slices of CPU time.
The time necessary to go through the gateway grows and keep getting longer to a stumble.
When everything is fresh, CAN messaging flies. When connection skeletons piles up, then gateway management crawls.
Not something Bosch architects ignore!
Most modules are instantly reset by cycling the ignition power.
However a small portion of the car is powered 24/7 non-stop to manage the wake-up signaling. I know F-SAM is one and I am going to guess its roommate CGW is two.
So let's streamline the reboot process by only targeting these two VIP modules fuses. What do you think?
More power to ya, no soldering this time.
Last edited by CaliBenzDriver; 07-21-2023 at 09:32 PM.
Reason: ⚡
Make good sense Cali, thank you.
The CAN is half duplex I read, so imagine so many modules taking turn to broadcast message and then N93 gateway got choked like airport during Christmas
Let me take a look deeper into the N10/1 Front SAM and figure out, where does N93 take power from within inside N10/1 ?
I basically have traced all fuses on N10/1 and none claimed to be for N93, well I never knew back then when doing that fuse check that N93 is inside N10/1 hahahaah.
N93 existence is only visible on a scanner or Xentry by it being visible as N93 in a full scan and the topo by Xentry.
Otherwise in all wiring diagram, we will never see N93, we will see only N10/1 front SAM.
Ok, let me re-visit N10/1 ........................
N93 close partners
I guess if you follow the dataline from the DLC connector it will lead you to what the diagram references as CGW N93... F-SAM N10/1?
Same thing with the A2 gateway, the diagram is going to reference what they are calling N93... N10/1?
It's time I drill my fuses to put them on a leash exactly like you did. Hopefully tomorrow so I can drive/report this Sunday...
N10/1 fuse would make an excellent "kill switch" for security and a "deep sleep" on-demand to discourage battery vampires wake-ups
Oke, I think I know how the N93 gateway and the N10/1 CPU gets the power.
First we re-read the description of Front SAM to get a better idea on how these two processors are different in duty and function.
We will call one as CPU and the other as N93.
Let's imagine the electronic section of Front SAM is a single PCB mother-board, not 2 separate PCB boards where N93 lives say on west side and the other one where the CPU lives being east side.
I been seeing this TRANSISTOR label thingy 2 years ago but never understood what it meant, except it is "electronic" thingy.
Now that you raised this N93 question, it all make sense
The good and bad news. Good is that now we learn, the bad news is that there is no way to reset N93 on its own, without removing battery power as in DISCONNECT battery
No reset button like our wifi router at home.
The CPU and the N93 gets double power, from 30g and 30. This set up is similar on my yachts for throttle and transmission controller which is managed by 1 module.
The power sources are 2, one from Left engine battery and Right engine battery, hence the diodes are there to prevent paralleling between 2 battery banks, while the device still get dual power source.
My "imaginary" duty separation between CPU and N93 . N93 wont be allowed to handle power, only data. CPU does the power switching as described by MB.
Here is a re-drawn CPU & N93 for its CAN BUS "imaginary" wiring, if I translate it correctly from the MB WIS.
What I wonder is, older model W212 with small 1.2ah battery inside the dashboard powering the N73 Ignition Switch as back up power, that one technically never sleep ever, even with main battery disconnect.
Will this N73 be the reporter when power is lost to N93 & CPU of N10/1 Front SAM and created stored codes which may confuse people ?
Here is my naked F-SAM getting a protective coating
facelifted SAM + CGW
I recall it's not a friendly module to repair.There are dozens of heavy solders that prevent access to the other component side of PCB.
Above picture shows two identical microcontrollers side by side.
Ouch, if only both side can get conformal coating .
When I can remove my Front SAM, I will conformal coat it too
I can get a good brand locally , spray type which I wanted to spray my UPS/Inverter for Bali home. I lost 2 UPS in 4 years.
1st UPS was insect sucked in and exploded, also corossion too.
2nd UPS, I filtered all air intake...... the coastal air killed the logic board hahahah. 18 months only.
I total loss total 4 TVs already in Bali, all from death by minor corossion. and none exceeded 4 years old. repaired 3 units too.
In memoriam of a great commercial sea diver: Fred Hurt who was diving regularly all the way to 79 years old.
He was the leader featured in White Water Gold-Rush. Thank you Sir 🙏
His relentless quest despite handicap was really inspiring.
I used to be licenced drysuit, search and rescue open water diver. Today's deep digging dedicated to his hard earned legacy.
So here is what I got for you... a big CAN MAP
Excuse the screenshots, the VM is hardly configured,
the Bookmarks don't work, got take pictures instead!
So I found the N93/7 they call it "chassis gateway" (bingo!) as well Flexray controller.
Its fuse power comes from N10/2... (why take the short route N10/1 ) .... of course this could be an entirely different device than N93 CGW.
FYI: I have not managed to get results from search by short names ("N93") - The tricky search tool is beyond my understanding to use at all.
To get anywhere I have to surf from diagram label to diagram label (the one with a pointed hand!) - It's so uneasy it feels results are random. I got to see lots of interesting stuff like ...
The CAN-E2:
Steering rack!
TPMS
RFK
Static LED L+R HL
N93!
Diagrams do show CAN-E2 going into N10/1, meaning N93 its being confused as F-SAM directly powered by 2x 150A pre-fuse links.
So, yeah my head is spinning now from all the deep WIS diving. R-SAM related assignment
I need to do more digging around N93/7 before I start pulling fuses, my reboot goal here.
++++ Questions to self regarding N93/7...
What is "DistroPlus" module ID ??
Search through CAN-E1 to find CGW??
Digest whole CAN gateways vs. solderless chaos.
Solderless MFK-Gateway crimpings are not DIY friendly for reassembly. Built-in high load heater supply helps its loose pins oxidize, gateway chaos distinction. Even single front camera has the same heater ordeal.
++++ Troubleshooting... Lottery!
There are so-so many different build options according to countless factors and preferences that each car is virtually a unique combination.
That makes it harder for anyone to diagnose issues without knowing what's involved from car to car.
One thing that always help is knowing what to expected. For that reason, diving around WIS interface is tough but excellent learning opportunity.
Last edited by CaliBenzDriver; 07-22-2023 at 09:21 PM.
07-21-2023, 04:31 PM
and none exceeded 4 years old. repaired 3 units too.
