BMW F20: CAN & FR Communication with FEM, Cluster, EPS

Hey there!
"As I'm writing a thesis on FlexRay communication, I'm trying to set up a "bench setup." I've connected FEM with the instrument cluster via CAN and FEM with EPS via FlexRay. Unfortunately, when I connect power (KL 15), the control units shut down after 14 seconds and don't even send any CAN signals. Since my parents also drive an F20, I removed the speedometer, connected it to CAN, and recorded a trace. I then played this trace back into my "bench setup," and it was observed that the ZGW (Central Gateway Module), which is located in the FEM, and the instrument cluster powered on. The instrument cluster displayed information like fuel level and engine speed, but it's a makeshift solution! =("
"Does anyone have a tip on how to keep the FEM alive without sending a complete data stream? I've heard that I need a key for the FEM... but I bought the FEM, EPS, and combination unit on **** , and a matching car key for the FEM wasn't included."

Hi,

I would proceed using the method of successive approximation.

Trace the "faulty data" within KCANMonitor, import it into the "Send and Replay" view, and save it.

Then, at each subsequent step, halve the list of CAN messages to be sent. If it works with one half, divide that half again; if it doesn't work, go back a step and continue with the other half.

Here's how you can achieve success with just a few simple steps.

Best regards, Rainer.

Hello,
Thank you for the quick response.
I once heard that in some vehicles, the CAN-Low line is briefly grounded or a voltage of up to 12V is applied to it to initiate wake-up signals from ECUs.

First, I recorded the data trace from the running engine onto my vehicle. Then, I filtered out the messages that are displayed on the monitor while the FEM and instrument cluster are active for 14 seconds after being turned on. Next, I sent the filtered messages to the FEM and instrument cluster via PT-CAN, ensuring that the messages don't overlap. With ISTA Plus, I can view the ECU tree, but only the ZGW and instrument cluster are displayed; the other ECUs are not shown... nor are the ECUs located within the FEM, because they are not being activated. If the FEM is not activated, I cannot initiate FlexRay communication with the EPS (Electric Power Steering).

According to Bosch, a car key should be able to physically activate the FEM (Front End Module) via CAS4 (Central Access Security System). However, since CAS4 is located within the FEM, I wonder if it might be possible to bypass something to activate the FEM directly.

Best regards,

CAN-Diagnose wrote:

Hi, I would proceed using the method of successive approximation. Trace the "faulty data" within KCANMonitor, import it into the "Send and Replay" view, and save it. Then, at each subsequent step, halve the list of CAN messages to be sent. If it works with one half, divide that half again; if it doesn't work, go back a step and continue with the other half. Here's how you can achieve success with just a few simple steps. Best regards, Rainer

How do you keep the cluster active?

The F20 uses AUTOSAR for network management, so if no wake-up signal is sent, the networks enter a bus sleep mode.

The network management IDs should be in the 500 range. Therefore, if you simulate NM message 0x57Fh (e.g., by sending it cyclically every 1000ms) and include a corresponding wake-up reason, at least the network management system should not put the network into bus sleep mode.

To keep nodes active, you need 2 active ECUs. I am simulating them via a vector interface (borrowed from the school). BMW does not use AUTOSAR, but Fibex.

postmann wrote:

How do you keep the cluster alive? The F20 uses AUTOSAR for network management, so if no wake-up signal is sent, the networks enter a bus sleep mode. The network management IDs should be in the 500 range. Therefore, if you simulate NM message 0x57Fh (e.g., sending it cyclically every 1000ms) and send a corresponding wake-up reason, at least the network management should not put the network into bus sleep mode.

Fibex is a file format that describes how communication is implemented, while AUTOSAR is an operating system, similar to OSEK.

You would need the following data for your CANoe:

It can be either a data basis in Fibex format (.xml) or an ECU Extract (.arxml). There are also AUTOSAR cluster extracts that describe an entire network; these also end with the .arxml extension.

You should be able to see the network management messages in CANoe and the "user data," which includes the reasons for waking up and staying active. If these are consistently present, it means that the bus is at least being kept alive by the network management system.

You are absolutely right.

I received a customized Fibex and I'm currently looking for a reasonable one, but no one seems to have it.

I found information about FlexRay WakeUp and the cause of wake-up in the Fibex documentation, but there's nothing mentioned about CAN. The Wakeup ID is used to simulate a wake-up event on the FlexRay transceiver, which would normally be used to activate inactive ECUs. However, since the Vector Interface handles this automatically, I haven't actually used the Wakeup ID feature yet.


Is there a standardized ID for diagnostics within the FlexRay protocol?

Best regards, Lennart.

I'm doing well.

BR EDDY