Since the first days of the N52 swap, the guidance has always been "You need to use the E85 ECU configuration on the MSV70 because E90 setup won't work...."
So we've done that and it's been fine.
Fast-forward to 2025 and I've wanted to upgrade my Garmin Catalyst to an Aim system that will let me do robust datalogging. I have all kinds of great information flying around that I'd love to capture! I have a Mk60E5 DSC with brake pressure (per corner!), ABS status, yaw and acceleration info and more. The ECU will give me throttle percentage, engine rpm and temp and so on.
The issue is that the E85 configuration uses the older CAN 11H protocol (K line) while my ABS was communicating with the newer BN2000 protocol with 28bit header IDs (PT CAN); I couldn't log both of them simultaneously, the Aim will do either K-line or PT CAN, but not BOTH.
In E90's both the DSC and the ECU share the same PT CAN bus, so why couldn't I convert the MSV70 to E90?
A huge "thank-you!" to nando for dusting-off his coding laptops and validating that this is possible. As he tells it, there's only ONE byte to flip in the flash to change from E85 to E90, but that unleashes a ton of follow-on effects.
First, the EKPM fuel control module needs to be changed from the 11H to the BN2000 protocol as found on the E90. There are several versions of the EKPM but generally they are much more available than the CAN 11h ones, the $40 version from Amazon actually works great! (I'll keep it as a spare). EKPM2 vs EKPM3 is an older design vs a newer one and there are some internal technical differences, but for a stock fuel pump the EKPM3 is fine. (N54 and turbo peeps that upgrade their fuel pumps to higher capacity versions have issues with the EKP modules overheating).
The EKP module sits directly on the PT CAN bus. This is a two-wire bus instead of the single wire K-line, which means that the bus needs to be resistor terminated appropriately. The total resistance across the two needs to be 60Ohms to reflect having a 120Ohm resistor on both sides of the net. Since I have the Mk60 which already has the second 120Ohm resistor my net was fine as-is.
The other issue we encountered is that the ECU was now expecting a shit-ton of other modules to be on the net and the car was in limp mode for having a mismatched power class. Nando sorted that out and when it came out of limp mode I felt like a kid again ;).
The upshot of all of this is that I now have an E90 PT CAN bus that my Mk60 and MSV70 share. Ironically, the MSV70 still communicates to the OBD plug over Kline, the E90's have a body module that translates PT CAN to OBD. I have the Aim connected and ALL of my parameters were available by choosing the "BMW PT6" streaming protocol. I have all of the long and lateral accelerations and Yaw data from the DSC, plus pressures and brake status. I have flags for when ABS intervention is active. I have all of the ECU parameters, from MAF to MAP to temps, rpm and so on. I will be adding oil pressure and temp. I could add suspension reading or tire temperature if I wanted!
CAN 11h out of an E85 or X3 vs the EKPM3
Mounted in my right-rear fender.
It's important to keep the PT CAN bus wiring tidy. This is a CAN hub that I borrowed from robotics. Works great without needing to solder and de-solder.
I have both the Aim and the Garmin, for now. The Aim lets me see ANY of the parameters in real time, plus it will log them automatically at the track or whenever I want on the street. I need to transfer some of my previous times from the Garmin to the Aim and then it's gone.
So we've done that and it's been fine.
Fast-forward to 2025 and I've wanted to upgrade my Garmin Catalyst to an Aim system that will let me do robust datalogging. I have all kinds of great information flying around that I'd love to capture! I have a Mk60E5 DSC with brake pressure (per corner!), ABS status, yaw and acceleration info and more. The ECU will give me throttle percentage, engine rpm and temp and so on.
The issue is that the E85 configuration uses the older CAN 11H protocol (K line) while my ABS was communicating with the newer BN2000 protocol with 28bit header IDs (PT CAN); I couldn't log both of them simultaneously, the Aim will do either K-line or PT CAN, but not BOTH.
In E90's both the DSC and the ECU share the same PT CAN bus, so why couldn't I convert the MSV70 to E90?
A huge "thank-you!" to nando for dusting-off his coding laptops and validating that this is possible. As he tells it, there's only ONE byte to flip in the flash to change from E85 to E90, but that unleashes a ton of follow-on effects.
First, the EKPM fuel control module needs to be changed from the 11H to the BN2000 protocol as found on the E90. There are several versions of the EKPM but generally they are much more available than the CAN 11h ones, the $40 version from Amazon actually works great! (I'll keep it as a spare). EKPM2 vs EKPM3 is an older design vs a newer one and there are some internal technical differences, but for a stock fuel pump the EKPM3 is fine. (N54 and turbo peeps that upgrade their fuel pumps to higher capacity versions have issues with the EKP modules overheating).
The EKP module sits directly on the PT CAN bus. This is a two-wire bus instead of the single wire K-line, which means that the bus needs to be resistor terminated appropriately. The total resistance across the two needs to be 60Ohms to reflect having a 120Ohm resistor on both sides of the net. Since I have the Mk60 which already has the second 120Ohm resistor my net was fine as-is.
The other issue we encountered is that the ECU was now expecting a shit-ton of other modules to be on the net and the car was in limp mode for having a mismatched power class. Nando sorted that out and when it came out of limp mode I felt like a kid again ;).
The upshot of all of this is that I now have an E90 PT CAN bus that my Mk60 and MSV70 share. Ironically, the MSV70 still communicates to the OBD plug over Kline, the E90's have a body module that translates PT CAN to OBD. I have the Aim connected and ALL of my parameters were available by choosing the "BMW PT6" streaming protocol. I have all of the long and lateral accelerations and Yaw data from the DSC, plus pressures and brake status. I have flags for when ABS intervention is active. I have all of the ECU parameters, from MAF to MAP to temps, rpm and so on. I will be adding oil pressure and temp. I could add suspension reading or tire temperature if I wanted!
CAN 11h out of an E85 or X3 vs the EKPM3
Mounted in my right-rear fender.
It's important to keep the PT CAN bus wiring tidy. This is a CAN hub that I borrowed from robotics. Works great without needing to solder and de-solder.
I have both the Aim and the Garmin, for now. The Aim lets me see ANY of the parameters in real time, plus it will log them automatically at the track or whenever I want on the street. I need to transfer some of my previous times from the Garmin to the Aim and then it's gone.
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