General guidelines:

1. Measure battery current (available in CAN-BUS gateway) live data when car is locked. The current should drop to low value no later than 5 minutes after locking the vehicle
2. Check all fault codes in ECUs and try to resolve as many as possible, leaving only irrelevant DTCs
3. Use coding in CAN-BUS gateway to discover if there are any ECUs that do not go into sleep mode (coding also displays measured consumption)
4. Check CAN-BUS Gateway live data to see which ECUs remain active after locking
5. Run autoscan with ignition OFF (PoCOM will display warning about ignition OFF) to see which ECUs respond (only gateway should be reachable)
6. You can try "ECU restart" coding in ECU that does not go to sleep mode; in some cases it is possible that ECU remains stock in some unexpected state, this may be a temporary solution to prevent battery draining until the issue is fixed

Coverage in PoCOM