Damp or soaked front carpets, a musty smell and fogged windows, and, when water reaches the footwell electronics, failed lights, windows or indicators. Most often the bulkhead scuttle drains block by the pollen filter and overflow into the cabin; perished door membranes and tailgate seals can add to it. Water then attacks the footwell module.
Check: Lift the front and rear carpets and press for damp. Check the boot and spare-wheel well for standing water, and confirm the scuttle drains near the pollen filter are clear.
ElectricalcommonDetectable at viewingevidence: documented60–200k km
Headlights, indicators, windows, wipers and central locking stop working at once, usually right after a battery change or a jump start. The module's memory corrupts when supply voltage dips. It is the single most common electrical failure on this generation.
Check: Test every window, both mirrors, the wipers, all exterior lights and the central locking before you drive. If any cluster of these is dead, this is why.
ElectricalcommonDetectable at viewingevidence: documented
Black screen, rebooting, refusal to read the drive, non-functioning navigation. The early CCC unit's hard drive and mainboard fail with age. Later CIC units are more reliable.
Check: Turn it on and use it for a few minutes: navigation, radio, settings. Reboots during that window are the fault showing itself.
ElectricaloccasionalDetectable at viewingevidence: documented
Oil seeping from the Valvetronic sensor on the side of the head; in the worst case oil tracks into the wiring. The sensor's seal hardens.
Check: Look at the intake side of the head for a wet sensor body and oil tracking down the loom.
ElectricaloccasionalDetectable at viewingevidence: documented100–200k km
Random electrical faults, warning lights that come and go, a battery that dies again within a year. The car's power management must be told a new battery was fitted. Cheap replacements are routinely fitted without coding, which then overcharges or undercharges the new battery.
Check: Ask when the battery was changed and whether it was registered. A car with a new battery, no registration and a scatter of odd electrical faults usually just needs coding.
ElectricalcommonPartly detectableevidence: documented