Smitha,
First, we need to straighten up some terminology: the SJA1000 is the CAN controller, not the transceiver. The Low Speed CAN Interface uses a TJA1054A transceiver. The controller handles the transmission and reception of messages; the transceiver operates at the bit level, shifting the digital signal levels to/from the SJA1000 to the higher voltage levelsfound on the CAN bus, among other things. A quick googling reveals that your MCP2551 transceiver is actually a High-Speed CAN transceiver, not a Low-Speed CAN transceiver.
The low-speed CAN interface will not work with this ECU as it uses different termination, hence the trasnceiver error.
Fortunately, you can change the transceiver on the PCMCIA-CAN interface. The transceiver is located in the little black box at the end of the dongle, and you can change these dongles for the correct high-speed CAN interface. You can obtain those dongles here. You'll need the HS/HS variety (or a HS/LS if you have other low-speed devices you want to use on the other port).
https://www.ni.com/en-us/support/model.pcmcia-can.html
More information on high-speed vs. low-speed CAN networks here:
https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z0000019LzHSAU&l=en-US
Hope this helps.
--Paul Mandeltort
Automotive and Industrial Communications Product Marketing
