1997 F-Body ECM

[JimCT_9C1]

I wanted to provide some more details on the OBDX Pro DVI mode setup and tests I ran in post 419 above -

The basic DVI configuration was straight from the documentation. I didn't need to set a filter. I just entered DVI mode, verified VPW protocol (was already set), opened the network, and sent the $10 commands. To clean up, I just closed the network and exited DVI mode.

Here is the list of commands I used to set up and run the DVI mode tests in post 419. After powering up the cable adapter and connecting to PC/terminal and vehicle:

Two commands in the default startup ELM mode (ascii input):

ATZ - restart device
DXDP1 - enter DVI mode

Then, the following commands once in DVI mode. Everything that follows is in hex:

31 01 01 CC - display current network protocol
31 02 02 01 C9 - open network

10 05 4C 10 F0 28 00 76 - send network command 4C 10 F0 28 00
10 05 4C 10 F0 27 01 76 - send network command 4C 10 F0 27 01
10 07 4C 10 F0 27 02 91 94 4E - send network command 4C 10 F0 27 02 91 94

31 02 02 00 CA - close network
31 02 06 00 C6 - exit DVI mode


Responses to network commands (from post 419 - spaces and line breaks added):

20 01 00 DE - acknowledge network send command
08 05 4C F0 10 68 00 3E - network response message 4C F0 10 68 00
20 01 00 DE - acknowledge network send command
08 07 4C F0 10 67 01 13 57 D2 - network response message 4C F0 10 67 01 13 57
20 01 00 DE - acknowledge network send command
08 06 4C F0 10 67 02 35 07 - network response message 4C F0 10 67 02 35



I realized that I could have configured the DVI network responses to be more like the ELM example and pared down a bit. So I suppressed the DVI cable acknowledgement of network send commands ($20 response), and enabled display of the PCM generated CRC/checksum in replies. Here are the DVI commands and responses for this case. I have included the responses to the DVI setup commands as well for reference:


DVI Mode commands (hex):

31 01 01 CC - display current network protocol
33 02 08 01 C1 - display CRC in network responses
24 02 01 00 D8 - suppress $20 replies to $10 network send messages
31 02 02 01 C9 - open network

10 05 4C 10 F0 28 00 76 - send network command 4C 10 F0 28 00
10 05 4C 10 F0 27 01 76 - send network command 4C 10 F0 27 01
10 07 4C 10 F0 27 02 91 94 4E - send network command 4C 10 F0 27 02 91 94

31 02 02 00 CA - close network
31 02 06 00 C6 - exit DVI mode


DVI Mode responses (hex with spaces and line breaks added):

41 02 01 01 BA - network protocol is 01 (VPW)
43 02 08 01 B1 - acknowledge CRC display in replies
34 02 01 00 C8 - acknowledge no $20 replies
41 02 02 01 B9 - acknowledge network open

08 06 4C F0 10 68 00 5E DF - network response message 4C F0 10 68 00 5E
08 08 4C F0 10 67 01 13 57 05 CC - network response message 4C F0 10 67 01 13 57 05
08 07 4C F0 10 67 02 35 7E 88 - network response message 4C F0 10 67 02 35 7E

41 02 02 00 BA - acknowledge close network
41 02 06 00 B6 - acknowledge exit DVI mode


Note the $08 network response messages are just the vehicle response with three additional bytes - two leading and one trailing. The two leading bytes identify this is as a network EDIT:response message and its length, and the trailing byte is the DVI checksum.

Hope this helps anyone following along who may want to give it a try.

Jim