I am using RealDash custom OBD2 XML with an OBDLink LX to communicate with an ECU over 29-bit UDS/ISO-TP (500k CAN).
Request:
- TX ID: 18DA3AF1
- RX ID: 18DAF13A
- Service: 22 52 06
The ECU returns a multi-frame ISO-TP response (67 bytes total).
I confirmed that RealDash receives at least the First Frame correctly.
For example, when ECU sends:
18DAF13A 10 43 62 52 06 00 0B 00
RealDash variables become:
B0=0x18=24
B1=0xDA=218
B2=0xF1=241
B3=0x3A=58
B4=0x10=16
B5=0x43=67
B6=0x62=98
…
So it appears that the CAN ID is included in the Bx buffer.
However, I also noticed that CAN IDs are still included even when using:
I cannot understand how Consecutive Frames are mapped into B variables.
The ECU continues sending CF frames correctly, but B12+ values do not match the expected ISO-TP continuation data.
Could you explain:
- how RealDash stores multi-frame ISO-TP responses internally
- whether B variables contain only the First Frame
- how Consecutive Frames can be accessed from XML
- and why CAN IDs are still included when ATH0 is used?
〇xml
ADS_OBD_6.xml (4.2 KB)
