[armenh7]

Vehicle: 2017 BMW 440i


Background information:
Client approached me with a no start issue. Codes in DME indicated EWS timeout. Scanned with ISTA and found lack of communication with modules on PT-CAN. After a bit of diagnosis, discovered there was a break somewhere between the KOMBI and FEM as the resistance was reading 120 instead of 60. Bridged the wires below which resolved the issue in regard to resistance and PT-CAN. All repairs were performed with the battery disconnected. Car was able to start successfully.

Issue:
Now, I'm unable to scan the car via ENET. OBD port has power and ground. When plugging in an MHD black wifi adapter, it creates the wifi network therefore indicating it has power and ground. The same adapter was being used prior to the repair to scan the car and it worked with no problem. The adapter was tested on another vehicle and it connected successfully. I was hoping it was just a coincidence but unfortunately I tried with an ENET cable and the issue persists. The computer does not detect anything on the ethernet port and the MHD adapter doesn't show a connection with the vehicle has been initiated (there's a green LED that lights up when connected). The OBD port pins 6 and 14 read 60 ohms indicating the terminating resistor is good but that doesn't matter for ENET. The OBD port pins all have continuity to the FEM for the ENET connections.
I tried undoing the repair for the PT-CAN and communication over ENET was not restored. I tried unplugging the headunit (it's the only module that uses ENET) and communication was not restored. We have tried disconnecting and reconnecting the battery multiple times to no avail. The car functions fine (engine runs and drives, cluster works, HVAC works, etc).

A replacement FEM is on the way but hoping to see if there's anything else I can check. All modules communicate fine over D-CAN.

[fe7565]

You should map out the PT-CAN components in both PT-CAN circuits (PT-CAN1 and PT-CAN2) and check where the two 120 ohm end terminator resistors are in each. Adding a 120 ohm resistor may temporarily restore a section of that canbus to communicatie, but may miss other components. There is redundancy built into some components like the GWS (gear shift) that has both PT-CAN(1) and PT-CAN2 circuit connections.


Troubleshoot continuity from one end of the bus' 120 ohm (end) device to the other end with the 120 ohm (end) device...component by component between them.

https://f30.bimmerpost.com/forums/sh...90&postcount=5

[armenh7]

Originally Posted by fe7565

You should map out the PT-CAN components in both PT-CAN circuits (PT-CAN1 and PT-CAN2) and check where the two 120 ohm end terminator resistors are in each. Adding a 120 ohm resistor may temporarily restore a section of that canbus to communicatie, but may miss other components. There is redundancy built into some components like the GWS (gear shift) that has both PT-CAN(1) and PT-CAN2 circuit connections.


Troubleshoot continuity from one end of the bus' 120 ohm (end) device to the other end with the 120 ohm (end) device...component by component between them.

https://f30.bimmerpost.com/forums/sh...90&postcount=5

Thanks for the reply but that's not what the post is about. That was the main issue the car had. Now that's fixed and ENET no longer communicates.

[fe7565]

Likely I misunderstood you.... I thought you restored comms by bypassing potentially faulty component(s) or wiring by adding a 120 ohm resistor so canbus communications was restored to EWS. Was the source of the problem (described in your "background") found?

ZGM (inside the FEM) is the conductor that "translates"between the various buses. Including ENET. Input (or lack of) from one bus may affect another bus.

If you have D-CAN working, ignore this below.

You said you checked for 60 ohms between D-CAN pin 6 and pin 14 of the ODB and it was good. Just to be 100%, I would check the ohm reading at the FEM side of these two D-Can wires Connector 8B pin 45 and 46): should be 60 ohms. And with the two D-CAN wires at FEM disconnected: should read 120 ohms between pin 6 and pin 14. And with the D-CAN wires at FEM disconnected, read ohms at the FEM Connector 8B pins 45 and 46: should read 120 ohms.



You have power at the OBD pin 16, so Fuse 12 is good. What about your two grounds at the ODB (earth-ground and electronics-ground)?

Do you have an oscope? Can you check D-CAN H and L? Or at least with a voltmeter for around 2.3V (L) and 2.7V-ish (H).


ENET not working:


Wiring is straightforward, but you said you already checked it.




ENET driver on your computer ok? ENET cable works on other car?

From another thread:

1) Make sure motor is running if car is not on a Charger.
2) Make sure EDIABAS.ini (for Tool32 or INPA) is set for Interface = ENET.
3) Make sure Windows Firewall is disabled
4) Make sure all Antivirus programs are disabled.
5) make sure LAN Adapter is set for DHCP and not using a Static IP.

Maybe the ZGM has a corrupt firmware affecting ENET, and may need to reflash it.

[armenh7]

Originally Posted by fe7565

Likely I misunderstood you.... I thought you restored comms by bypassing potentially faulty component(s) or wiring by adding a 120 ohm resistor so canbus communications was restored to EWS. Was the source of the problem (described in your "background") found?

ZGM (inside the FEM) is the conductor that "translates"between the various buses. Including ENET. Input (or lack of) from one bus may affect another bus.

If you have D-CAN working, ignore this below.

You said you checked for 60 ohms between D-CAN pin 6 and pin 14 of the ODB and it was good. Just to be 100%, I would check the ohm reading at the FEM side of these two D-Can wires Connector 8B pin 45 and 46): should be 60 ohms. And with the two D-CAN wires at FEM disconnected: should read 120 ohms between pin 6 and pin 14. And with the D-CAN wires at FEM disconnected, read ohms at the FEM Connector 8B pins 45 and 46: should read 120 ohms.



You have power at the OBD pin 16, so Fuse 12 is good. What about your two grounds at the ODB (earth-ground and electronics-ground)?

Do you have an oscope? Can you check D-CAN H and L? Or at least with a voltmeter for around 2.3V (L) and 2.7V-ish (H).


ENET not working:


Wiring is straightforward, but you said you already checked it.




ENET driver on your computer ok? ENET cable works on other car?

From another thread:

1) Make sure motor is running if car is not on a Charger.
2) Make sure EDIABAS.ini (for Tool32 or INPA) is set for Interface = ENET.
3) Make sure Windows Firewall is disabled
4) Make sure all Antivirus programs are disabled.
5) make sure LAN Adapter is set for DHCP and not using a Static IP.

Maybe the ZGM has a corrupt firmware affecting ENET, and may need to reflash it.

Thanks for the detailed response.

D-CAN is functional.

The issue was the cluster wasn't being seen on the PT-CAN when doing the resistance measurement for terminating resistors. The wires from the cluster to the FEM connector were fine, but for some reason there wasn't continuity between 7B and 8B of the FEM connectors. I just bridged the PT-CAN wires between the two connectors and it restored comms and satisfied the CAN resistance value of 60 ohms. Only the cluster uses PT-CAN on the 7B connector so the fix done shouldn't be problematic. I followed it from another thread with a guy having a CAN issue. (Turns out it was your thread lol, very useful by the way so thank you for that)

Two forms of ENET were tested:
MHD ENET adapter
ENET cable
Both verified working on another car. The MHD ENET adapter was being used on this car initially.

I haven't tried with the car running. I did get that idea today. I'll try out it and see if there's a difference. All prior diagnosis was done with just the ignition on. Battery charger connected the entire time. It's 100% a car side issue, not computer configuration issue as the MHD app doesn't see the car either.

I agree with the FEM software being problematic, however I don't have a way to flash it over DCAN using BMW tools (ISTA or ESYS).

Last night I verified at the OBD port that when an ENET cable is plugged in, pin 8 gets 12V. However, I haven't checked that at the FEM side. I'll try that as well. Now, given the pin had continuity from the OBD port to the FEM, I imagine it'll be fine. When checking continuity, I had an ENET cable plugged in and was measuring from the backside to ensure it wasn't a loose pin.

[fe7565]

Could bench flash the FEM. Unfortunately, it requires some specialized equipment, I gather.

[Siki78]

Did you try esys to connect over gateway too or just over vin?

[fe7565]

Originally Posted by Siki78

Did you try esys to connect over gateway too or just over vin?

Would that give access to the ZGM directly? If yes, should definitely try it.