Peugeot 308 T9 1.6 BlueHDi

The BlueHDi emissions system relies on AdBlue injection into the SCR catalyst. The AdBlue injector can crystallise and block, while the pump (built into the AdBlue tank) fails when fluid contaminates its circuit board. NOx sensors also fail, triggering fault codes P2200, U029D, or P20EE. A NOx sensor replacement costs around €600-750 at a dealer. If the entire AdBlue tank and pump need replacing, costs reach €1,500-2,200. The issue typically appears after 80,000-120,000 km, particularly if the car sits unused for extended periods or if low-quality AdBlue is used. A standalone injector replacement at a specialist costs around €300-400.

The 1.6 BlueHDi uses an additive-assisted DPF (Eolys/cerine system) that lowers the regeneration temperature. Despite this, short trips under 15 minutes prevent the DPF from reaching regeneration temperature. Symptoms include the engine warning light, anti-pollution fault message, and reduced power. A professional DPF clean costs €300-500. Full DPF replacement costs €800-1,500 including fitting. The Eolys additive tank also needs topping up approximately every 120,000 km (around €150 at a dealer). Using the correct low-SAPS oil is essential to prolong DPF life.

The EGR valve on the DV6 engine accumulates carbon deposits over time, especially with gentle driving and short trips. Symptoms include rough idling, loss of power, the anti-pollution warning, and fault codes P0490 or P1162. Cleaning the EGR valve costs around €150-250 at an independent garage, but if the valve is beyond cleaning, replacement costs €400-900 depending on whether aftermarket (around €100-150 for the part) or OEM (around €300) parts are used. Euro 6.1 versions had a known batch issue requiring EGR replacement under a service action.

The 1.6 DV6 turbo can fail if oil feed lines become blocked with carbon deposits. This happens primarily when oil changes are delayed or incorrect oil is used. The engine produces relatively high amounts of carbon, and sludge can starve the turbo bearings of lubrication. Symptoms include blue or black smoke, whistling sounds, and significant power loss. Turbo replacement costs €1,200-2,500 including the mandatory fitting kit (strainer, hoses, seals). The issue is preventable with strict oil change intervals using the correct low-SAPS oil (PSA B71 2312 specification) and allowing the turbo to cool down after hard driving.

The dual mass flywheel on the 1.6 BlueHDi can develop excessive play, causing juddering when moving off in first gear. Some 2015 models had premature clutch and DMF failures that were covered under warranty. For out-of-warranty cars, a complete clutch and DMF replacement including slave cylinder and release bearing costs €1,000-1,800 depending on whether done at a dealer (around €1,600) or independent specialist (around €1,000-1,200). Labour time is approximately 7 hours. Solid flywheel conversion kits exist as a cheaper alternative.

If the 308 is equipped with the EAT6 automatic (Aisin TF-80SC), the valve body solenoids can become contaminated, causing harsh or jerky shifts, especially between 1st and 2nd gear. The issue is worsened by Peugeot's claim that the gearbox oil is a lifetime fill, which many specialists dispute. A valve body overhaul costs €600-900 at a specialist. Full gearbox rebuild can reach €1,500. Prevention: change the ATF every 60,000 km despite the manufacturer's claim. Manual gearbox versions are not affected.

The T9 308 has a known issue with premature front shock absorber failure, often accompanied by spring breakage. Peugeot released updated parts to address the problem. Symptoms include knocking noises over bumps and uneven tyre wear. A pair of replacement shock absorbers costs €200-400 for parts, plus €200-400 for labour. If springs also need replacing, add approximately €150-200. The issue typically appears between 60,000-100,000 km.