Peugeot 508 (Gen 2) Common Problems & Reliability
The second-generation Peugeot 508 (2018–2024) stands out in the UK executive car segment with its striking, low-slung design, frameless windows, and high-tech "i-Cockpit" interior. While it is a significant improvement in quality over its predecessor, prospective owners must be aware that it is a complex machine with specific mechanical and electrical sensitivities. Diligent maintenance is not optional if one is to avoid expensive repairs common to this generation. A critical point of concern for petrol variants is the 1.2 PureTech engine, which utilizes a "wet belt" timing system that runs submerged in engine oil. The long-term durability of this component is entirely dependent on adhering to stringent service intervals and using the precise oil viscosity mandated by PSA; failure to do so can cause the belt to degrade, with rubber particles potentially clogging the oil pump and leading to catastrophic engine failure. It is imperative that any used 508 features a documented, full service history from a Peugeot Main Dealer. Diesel models (BlueHDi) are fundamentally robust for long-distance users, provided the AdBlue emissions control system is maintained correctly. The internal components of the AdBlue tank, including the pump and sensor, are a documented weak point, with failure typically necessitating a costly full-tank assembly replacement. Furthermore, drivers of diesel 508s should ensure regular motorway driving, as vehicles restricted to short urban journeys are prone to Diesel Particulate Filter (DPF) clogging, a condition that can lead to limp-mode operation and subsequent damage to turbocharger components. Finally, while electrical issues are frequently reported, they usually manifest as non-catastrophic software glitches—such as infotainment freezing or sensor errors—rather than complete system failure. Many of these quirks are resolved through dealership firmware updates. Additionally, owners of the frameless-window models should exercise caution during freezing UK winters, as forcing frozen windows open can damage the regulator mechanism or the seals. With consistent, preventative maintenance, the 508 Gen 2 offers a sophisticated executive package, but it demands an owner who is committed to its specific upkeep requirements.
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Detailed fault breakdown, symptoms, and estimated repair bills by production year.
Most Common Peugeot 508 (Gen 2) Faults & Repair Costs
AdBlue / BlueHDi Emissions Failure
On 1.5 BlueHDi (DV5) and 2.0 BlueHDi (DW10) diesel engines, the integrated AdBlue SCR tank system is a frequent failure point. The internal dosing pump, heating element, or tank pressure sensors suffer electronic faults or urea crystallization, or the tank deforms. This triggers an amber UREA warning, emissions engine fault light, and an unyielding countdown preventing engine restart once the countdown reaches zero. Rectification typically demands replacing the entire sealed plastic tank assembly, as individual pump and sensor modules cannot be serviced separately.
UREA warning light and engine management light illuminated, Dashboard alert warning of non-start countdown in miles, White urea crystallization crust around tank filler neck
- Check instrument cluster for any active or stored emissions warning messages
- Verify service records for previous AdBlue tank or injector replacements
- Inspect the boot well and filler neck area for crystallized urea deposits
Frameless Window Issues
The fastback coupe styling of the 508 Gen 2 uses frameless side glass that must automatically drop slightly when the door handle is pulled and rise into the weatherstrip upon closing. In freezing UK winter conditions, the glass frequently freezes solid against the rubber seals, causing the anti-pinch mechanism to trigger or damaging the electric window regulator cables and plastic clips. Over time, worn or dry window seals also lead to wind buffeting, high-speed cabin whistle, and damp ingress along the door cards.
Noticeable wind whistle and air rushing noise from the door glass at motorway speeds, Window fails to drop automatically when opening the exterior door handle, Window regulator motor strains, clicks, or binds inside the door shell
- Operate every window switch to verify smooth drop-and-raise indexing upon opening and closing
- Inspect rubber weatherstrips along the roof pillar for tearing, cracking, or hardening
- Listen for wind noise leaks and mechanical clicking while driving at motorway speeds
1.5 BlueHDi Camshaft Timing Chain Failure
The 1.5-litre BlueHDi (DV5) diesel engine built prior to early 2023 utilizes a 7mm auxiliary timing chain linking the twin overhead camshafts, independent of the external timing belt. Due to carbon buildup and high stress, the 7mm chain prematurely stretches, slaps against the rocker housing, and can snap without warning. Chain failure throws camshaft timing out of phase, causing valves to collide with pistons and requiring cylinder head rebuilding or full engine replacement. Peugeot later engineered an upgraded 8mm chain kit with modified camshafts under safety campaigns.
Metallic ticking or rattling sound from the top of the cylinder head on cold startup, Rough idle and sudden engine management light with camshaft sensor correlation codes, Complete engine stall and refusal to restart following sudden chain rupture
- Listen carefully near the top camshaft cover for metallic rattle during a cold start
- Verify dealer service documentation to confirm if the 8mm chain upgrade kit has been installed
- Check that annual engine oil changes used PSA B71 2010 or PSA B71 2290 compliant oil
1.2 PureTech Wet Timing Belt Degradation
On 1.2 PureTech petrol models, the engine uses a wet timing belt running directly submerged in hot engine oil. Using incorrect oil formulations, short urban trip fuel dilution, or age causes the belt's rubber compound to crack and shed fibrous debris. This dislodged debris collects in the oil sump and clogs the oil pump pickup strainer screen, causing oil starvation, brake vacuum pump loss of servo assistance, and eventual bottom-end engine seizure. Stellantis lowered the belt replacement interval and issued technical service actions.
Low engine oil pressure warning light illuminated under load or braking, Spongy or hard brake pedal caused by degraded vacuum pump operation, Surface swelling, cracking, or edge fraying visible on the timing belt
- Inspect the timing belt through the oil filler aperture using a dedicated PSA belt width gauge
- Check oil filler neck and dipstick for particulate rubber contamination
- Verify full main-dealer or specialist service history with certified PSA B71 2297 or B71 2010 oil
i-Cockpit Touchscreen and Digital Cluster Glitches
The i-Cockpit system on the 508 combines a 12.3-inch configurable digital instrument cluster with an 8-inch or 10-inch central touchscreen running NAC infotainment firmware. Software stability issues, slow telematics processors, and loose rear harness grounds frequently manifest as frozen displays, complete touchscreen blackouts, lost Bluetooth or smartphone mirroring connectivity, and delayed heater controls. In most instances dealer ECU and telematics firmware reflashes cure the glitch, though hardware screen replacement is occasionally required.
Central touchscreen freezes or goes completely black while driving, Delayed response when adjusting climate controls or heated seat toggles, Apple CarPlay and Android Auto intermittent connection drops
- Test climate control response across all physical piano keys and screen submenus
- Verify Bluetooth pairing and wired smartphone mirroring for stable audio playback
- Check digital instrument cluster for pixel corruption or reboot cycles on startup
Plug-in Hybrid On-Board Charger and High-Voltage Battery Faults
On 508 Hybrid 225 and 508 PSE (Peugeot Sport Engineered) plug-in hybrid variants, the single-phase on-board charger (OBC) module or charging port solenoid can fail to lock or handshake with UK Type 2 wallboxes. Additionally, software calibration faults within the battery management system (BMS) can trigger traction system warnings, refuse to engage pure Electric mode, or throttle electric motor assist. In rare cases internal cell imbalance in the 11.8 kWh traction pack requires high-voltage technician intervention.
Traction battery fault message appearing on the digital instrument panel, Charging port indicator light flashes red and stops charging prematurely, Vehicle refuses to enter pure Electric mode despite showing an indicated charge
- Plug car into a charging point and verify normal handshake and steady charging light
- Cycle drive modes between Hybrid, Sport, and Electric on the test drive
- Check dealer service record for high-voltage battery health certificates and BMS software updates
Buying a used Peugeot 508 (Gen 2)? Always check for hidden finance and write-off history.
Mechanical problems are only half the battle. Over 1 in 3 UK used cars checked have unpaid finance or accident write-off records that could cause you to lose the car or thousands in value.