CAN Operating Hour Meter

Hello,

While hacking into the CAN bus of my Mondeo, I discovered a value that was increasing every second in ID 080h. This ID is transmitted 4 times per second on both the MS-CAN and the Comfort-CAN, but NOT on the HS-CAN (PCM).

ID | DLC | D0 | D1 | D2 | D3 | D4 | D5 | D6 | D7 | Period (ms)
080 8 10 0A 15 12 25 0F 00 00 250

At the time I was observing, only bytes D4 and D5 were changing (turning orange), with D5 clearly being the least significant byte and overflowing into D4.
However, the values of D2 and D3 also changed between the scans. The values of D0, D1, D6, and D7 remained static at these levels across multiple scans.

If I consider bits D2 through D5 as a single number (32 bits), then these time values would be implausible, even if the counter had never been reset. If I only use bits D3-D5, I get a cycle time that doesn't correspond to anything. Similarly, using only bits D4-D5 would also be implausible because I know I have only been in the vehicle for half an hour, and it was stationary for a longer period beforehand.

'That type of timer probably isn't typical for Ford, but is likely found in all vehicles? Perhaps even with the same ID?'
How does that work over there? Does the value perhaps simply reset to 00 00 at 16 bits (which would still be almost 18 hours)?
The values of D2 and D3 could potentially represent something entirely different at random.

"I haven't come across that information regarding VAG yet... I'm sure the operating hours are documented somewhere, but I don't know if they are transmitted on any of the CAN buses."

Best regards, Rainer.

Hey,

What you're seeing there is very likely the time, and it's represented in bytes (with increasing offset).

Byte 1: Year (last two digits).
Byte 2: Month.
Byte 3: Day
Byte 4: Hour.
Byte 5: Minute.
Byte 6: Second.

At least, that's the case with my Fiesta Mk7.

text
// Edit: So, byte 1 = D0, etc., and D6-D7 are probably always 00.