Can Simulator

Hi everyone

I installed a parking heater from an Audi into my Skoda.
Unfortunately, it won't start because it's not receiving a signal from the CAN bus regarding the fuel level.
What's the easiest way to let her know that the tank is full?
Unfortunately, I haven't really delved into the CAN bus yet.
Soldering is no problem.
And I also have enough measuring instruments .
I only lack the specialized knowledge .

I would be grateful for any help you can provide.

Okay, you'll need a controller that supports the CAN protocol. My minimal solution is the AT90CAN32 (or 64/128, which are sometimes not even more expensive), but there are similar options from other manufacturers if you prefer PIC microcontrollers over AVR, for example.

And then you need to have the correct CAN matrix – or you'll have to experiment on a working car to figure out where the fuel level information is located.

I have a programmer for AVR microcontrollers.
Can I connect it directly to the bus?
And for CAN beginners... What is a CAN matrix?

Hallo,

die CAN-Matrix sagt aus, welche Daten in den CAN-Bus Nachrichten was bedeuten.

Viele Grüsse, Rainer

Quote:

I have a programmer for AVR microcontrollers. Can I connect it directly to the bus?

Almost. You still need a CAN transceiver in between.
e.g., PCA82C250 (high-speed, also works on the low-speed bus but then without single-wire operation and waking up from bus idle), or TJA1054 (low-speed).

Quote:

And for CAN beginners... What is a CAN matrix?

"As my colleague has already mentioned, the term originated when Bosch, shortly after inventing CAN, thought, 'Let's simply create a matrix [table] where we put the message IDs in the far-left column, and then in the 64 columns to the right, we specify what each of the individual (of the maximum 8x8) bits means within that particular message.'"

Because my assumptions turned out to be correct...
Only 'The Matrix' confused me.
I think someone in this forum might know the address where the fuel level signal is located.

Stecker vom Tankgeber an eine "Simulation" anschliessen und schauen, wie sich die Werte in den CAN IDs verändern.

Because all I need to do now is get a speedometer and a CAN adapter.
Unfortunately, the Audi is no longer available.

Please pay attention to message with ID 621.
Byte 4, bits 0 through 6, indicate the content within the range of values from 0 to 126 .

Regards,
Maxx.

First of all, thank you to everyone.
I'm not sure yet if I can implement it.
I've only recently started working with digital electronics. Otherwise, I was 'just' an analog person .

Quote:

Pay attention to the message with ID 621. Byte 4, bits 0 through 6, indicate the content within the range of values from 0 to 126

.

Just out of curiosity:
I would have expected that bytes 3, bits 0 to 6, are located in ID 800 (0x320), which corresponds to the fuel level sensor on the instrument cluster.
Does the ID 621 originate from a fuel sensor/fuel pump that is directly connected to the bus?


Best regards,
Ingo

I can only say for sure that the heating system is connected to the chassis scan.
According to the wiring diagram, the sensor connects directly to the speedometer (without using a communication bus).

Quote:

I can only say with certainty that the heater is connected to the chassis scan.

There's no chassis available from the VAG group. So it's probably related to the drivetrain.

CAN drive.
CAN combination (only if the gateway is not in the combination).
CAN diagnostics.
CAN Comfort (== may be combined in some models ==)
CAN Infotainment

Quote:

And according to the wiring diagram, the sensor goes directly to the speedometer (without a bus)

.

Then, see my suggestion.

Best regards,
Ingo

There are...

CAN-Bus chassis/control panel insert.
CAN-Bus Comfort Features.
CAN-Bus diagnostics.
CAN bus drive.

From an original wiring diagram.

Audi A4 2008.

Quote:

There are... CAN-Bus chassis/control panel insert. CAN-Bus Comfort Features. CAN-Bus diagnostics. CAN bus drive. From an original wiring diagram. Audi A4 2008

Unfortunately, I'm not really an expert on audio equipment, but this is now bothering me.
Okay, since you already have the wiring diagram, where is the gateway located, and what else is connected to the "CAN bus chassis/control panel module" besides the instrument cluster? Or isn't the ABS/ESP system connected to the CAN drivetrain?

Best regards,
Ingo

Hallo,

das Gateway ist die zentrale Schaltstelle an die alle CAN Busse angeschlossen sind. Es stellt über CAN-Diagnose (am OBD2-Stecker) eine Schnittstelle zu den anderen Steuergeräten her.

Viele Grüsse, Rainer