A parasitic draw can flatten a Peugeot 408 battery overnight even when it’s parked. Here’s what to check first and when driving is still safe.
Why a parked Peugeot 408 drains its battery
If your 408 is dead every morning, you’re not imagining it — something is staying awake after shutdown. Modern Peugeots use a BSI, comfort CAN network, keyless entry and often telematics, and all of those should go to sleep within roughly 30–60 minutes. If a latch switch, lamp, add-on accessory or control module keeps waking the network, you get a parasitic electrical draw. Common culprits include a boot or tailgate light staying on, a glovebox or vanity lamp, faulty door/bonnet/tailgate microswitches, an aftermarket dashcam/alarm/tracker wired to a permanent live, a radio or head unit that won’t sleep, a leaky alternator diode, or simply an aged battery with little reserve left.
