The Engine Clean approach: confirm the complaint, measure the system and isolate the circuit before components are blamed.
Sleep mode is a coordinated process
Modules exchange messages, save information and wait for conditions such as doors closed, keys absent and timed tasks completed. A switch, sensor, network message or software state can prevent the expected shutdown sequence.
The module drawing current may not be the instigator
One unit may appear active because another component keeps sending wake-up traffic. Condemning the busiest module without checking the network can replace the effect rather than the cause.
Common clues need testing
Door and boot status, keyless-entry activity, infotainment faults, water ingress, aftermarket equipment, damaged wiring and recent coding or repair can all be relevant. None should be blamed without evidence from the affected vehicle.
Capture the shutdown and wake-up pattern
Current monitoring can be combined with network, diagnostic or circuit checks to establish when the event occurs. Intermittent cases may need extended logging because connecting test equipment or opening a door can change the behaviour.
Common questions
Before you book electrical testing
How do I know whether a module is awake?
Current pattern, network activity, status data and targeted circuit tests can provide evidence. A scan tool showing communication alone does not necessarily prove an abnormal wake state.
Can keyless entry keep waking a vehicle?
It can be relevant on some vehicles, but keys, receivers, handles, settings and other network activity must be tested rather than assumed.
Does the faulty module always need replacing?
No. Wiring, connectors, configuration, software, connected components or an external wake request may be responsible. The repair follows the confirmed evidence.