Peugeot 508

The NiMH high-voltage battery of the Hybrid4 system loses capacity significantly after 8–10 years or 150,000 km. Below 70% residual capacity the system disables the electric drive. Replacement is extremely expensive.

Symptoms: Electric drive mode no longer available, sharply declining EV range, hybrid warning light, increased diesel consumption

The inverter that converts battery energy for the rear-axle electric motor can fail. Fault messages and power limitation follow. PSA carried out recall campaigns for affected model years.

Symptoms: 'Hybrid System Fault' message, power limitation, no four-wheel drive, multiple warning lights on instrument cluster

The inverter for the 37 kW rear electric motor in the Hybrid4 system reports sporadic faults. Fault codes U1213 and similar are stored. The system switches to combustion-engine-only mode and deactivates four-wheel drive.

Symptoms: Warning 'electric drivetrain fault' or 'motor electrical unit fault', 4WD automatically deactivated, reduced power

The common-rail injectors of the DW10 diesel engine can fail from as early as 80,000 km when maintenance is poor. Defective injectors cause rough engine running and, in the worst case, oil dilution in the crankcase.

Symptoms: Cold-start problems, rough idle, knocking, increased diesel consumption, engine warning light

The diesel particulate filter clogs during predominantly short-trip use because the automatic regeneration cannot run to completion. In hybrid mode the diesel is shut down more frequently, making regeneration even harder.

Symptoms: DPF warning light, power limitation, increased fuel consumption, engine limp mode when severely blocked

The EGR cooler on the 2.0 HDi in the Hybrid4 system tends to leak due to thermal stress. Coolant loss can cause overheating of the combustion engine, which is particularly critical in Hybrid4 operation as the electric motor cannot compensate for cooling.

Symptoms: Coolant level drops inexplicably, white smoke from the exhaust, fluctuating heater output, elevated engine temperature

The braided steel-mesh line between the engine block and turbocharger becomes brittle and develops widespread oil leaks. Peugeot's replacement is a rigid pipe. In Hybrid4 operation increased fire risk from oil contact with hot exhaust components.

Symptoms: Oil patches on the ground after parking, oil smell while driving, oil mist in the engine bay, rising oil consumption

Broken suspension springs are among the most common TÜV/MOT failures on the 508 I. Particularly the rear springs break at their ends and can prevent an MOT pass.

On 508 models from 2011 an insufficiently tightened wiper arm bolt can cause the wiper to stop working in the rain. Affects vehicles from build year 2011.

On diesel models from build years 2013–2014 the fuel filter heater connector can overheat and cause a fuel leak. Fire risk if the seal fails.

The timing chain on the 1.6 THP and VTi petrol engines in the 508 I stretches prematurely through defective chain tensioners and long oil change intervals. In the worst case the chain snaps, causing catastrophic engine damage.

Water enters the boot on the 508 I through leaking tailgate or rear light seals. The spare wheel well gets wet. Damp electronics in the boot can cause consequential damage.

Alongside the known spring failures, shock absorbers and rear axle rubber bushes on the 508 I also wear prematurely. Particularly at higher mileages over 120,000 km rear axle behaviour deteriorates noticeably.