A module may fail to enter its expected operating state even if its communication interface can function once awake. Wake-up behaviour and ongoing message exchange should therefore be described separately.
Record the first response
State which normal vehicle action should wake the system and whether another action changes the result. Include parked duration and whether a diagnostic session itself appears to restore operation. That observation can change the test conditions.
A technician should identify the intended wake-up routes and supplies before replacing a controller. Do not keep a vehicle permanently awake as a workaround. Verification should include the transition from the relevant parked state, not only communication after a scanner has already activated the system.
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