Hi,
Because, it is still not clear what you do I attached an example for CAN and S12ZVL or S12ZVC.
In both examples the loopback mode is used so the communication is not visible at pins. This provides you to learn CAN communication.
However, if you want to test the CAN with transceiver connected you need a real bus to manage error statuses. For thi it is suitable to read CAN specification. https://www.nxp.com/docs/en/reference-manual/BCANPSV2.pdf
Moreover, you can test the can without a transceiver ... see https://www.mikrocontroller.net/attachment/28831/siemens_AP2921.pdf
If the CAN is enabled at pin then CAN peripheral takes precedence over all peripherals available at the pin wit less priority.
If it is still not enough you can use paid version of the CodeWarrior eclipse and ProcessorExpert implemented in it and you can include CAN modules into the project.
Best regards,
Ladislav