Diagnostics communication: TCM: Notes
WARNING: This page is about a different car, the 2001 Saab 9-3. However, it is still accessible from the selected car via links, so may be relevant.
If TCM is contacted, the diagnostic tool will first call DICE and request diagnostic communication with TCM. DICE transfers the diagnostic tool request to the I-bus, whereby MIU will transfer the diagnostic request to the P-bus and TCM.
This means that DICE and MIU must both be powered (awake) in order to contact TCM.