Peugeot 308 PHEV P51

The 308 PHEV uses a MAHLE-supplied on-board charger integrated with the DC-DC converter in a single module. This unit has documented reliability issues across the Stellantis PHEV range, affecting Peugeot, Citroen, DS, and Opel models built from 2019 onward. When the OBC fails, the car can no longer charge via Type 2 AC (home wallbox or public charger). Some owners report the car showing 'charging complete' while the battery is actually empty. The module contains eight circuit boards with an epoxy-bonded IGBT output board, making repair difficult. Stellantis extended the OBC warranty from 2 to 4 years (from April 2021) and switched suppliers around 2024. A new OEM replacement costs approximately €2,200-3,800 including labor, as it requires significant rear disassembly. Remanufactured units from specialists like Actronics have become available at lower cost. Verify the car charges correctly from a wallbox during the test drive.

Stellantis recalled over 90,000 PHEV vehicles (including the 308) across the EU for battery-related issues. The main concerns are: faulty battery monitoring software that could incorrectly detect cell voltage and temperature, causing unexpected engine shutdown (2022 production); water infiltration causing corrosion of the battery reinforcement and box, with potential fire risk (2019-2023 production), addressed by drilling water drainage holes; and cell voltage mismatch in early production units. All recalls are free at Peugeot dealers. The Peugeot Care warranty covers the HV battery for 8 years / 160,000 km with a 70% capacity guarantee. If the traction battery needs replacement outside warranty, expect €3,000-5,000 for a refurbished pack or €6,000-8,000 for a new OEM unit. The cost entry shows €0 at the low end because most known issues are covered by recall campaigns or the 8-year battery warranty.

The P51 308 uses Stellantis's latest infotainment platform with a 10-inch central touchscreen. Early 2021-2022 production cars suffer from software instability: the screen freezes mid-drive, the system reboots spontaneously, Bluetooth audio cuts out, and Apple CarPlay or Android Auto disconnects. A specific issue on hybrid models is the touchscreen overheating and going blank in warm weather, with owners reporting the system detects no cooling fan and shuts down to protect itself. The digital instrument cluster can also flicker briefly. Most cases are resolved by dealer firmware updates or over-the-air updates (free). Persistent issues after multiple reflashes may require head unit replacement at €800-1,200. The system improved significantly through 2023-2024 firmware releases. A temporary fix for most freezes is holding the power button for 10 seconds to force a reboot.

The PHEV system depends heavily on the 12V service battery for its electronics. If the car sits unused for several days, the 12V battery can drain, causing cascading faults: 'Electric mode not available' warnings, airbag/pretensioner warning lights, and engine management errors. The DC-DC converter (part of the OBC module) is supposed to keep the 12V battery charged from the HV battery, but if the OBC module is partially faulty or the 12V battery itself has degraded, this charging loop fails. Replacement of the 12V battery costs €150-250, but if the root cause is the DC-DC converter within the OBC module, the repair escalates significantly. Short-trip driving exacerbates the problem. Keeping the car on a trickle charger when parked for extended periods helps prevent the issue. Some owners report the Peugeot dealer solution is simply to replace the 12V battery, which works if the underlying OBC module is healthy.

This is a widely reported characteristic rather than a defect. The 308 PHEV claims 59 km WLTP electric range (12.4 kWh battery), but real-world testing consistently shows 30-45 km in mild weather and 20-25 km in winter. The main culprit is the cabin heating system, which draws heavily from the battery. A Danish winter test showed 30 km with heater on versus 51 km with only heated seats. Some owners report their initial 50+ km range dropping to 35 km after 12-18 months, though this is partly seasonal and partly genuine capacity loss. The system also forces the petrol engine to run periodically if it hasn't been used recently (to prevent corrosion and humidity buildup), further reducing electric-only capability. Using heated seats instead of the full climate system, preconditioning while plugged in, and driving in B mode for maximum regeneration all help extend range. The 2025 facelift with the larger 17.2 kWh battery addresses this somewhat.

The e-EAT8 is a modified Aisin 8-speed torque converter automatic adapted for hybrid use. Some owners report a brief surge or hesitation moving from first to second gear during gentle acceleration, and slight shuddering in slow stop-start conditions. The torque converter lock-up calibration and the transition between electric and petrol power contribute to the uneven feel. In most cases, a TCU software update at the dealer resolves the issue (€100-300). If the transmission fluid has degraded from predominantly urban driving, a fluid change can help (despite Peugeot claiming it is a lifetime fill). More serious valve body issues are rare but cost €1,500-2,500. The 2025 facelift replaced the e-EAT8 with a new 7-speed dual-clutch transmission.

Peugeot recalled 308 models manufactured between May 2023 and January 2025 (recall MWY) for a defect in the threaded connection between the high-pressure fuel pump and the fuel rail. If the connection loosens, fuel can leak in the engine bay near ignition sources. A separate recall (MUN) covers February 2023 to September 2024 production for similar fuel leak concerns affecting about 2,100 vehicles worldwide. Both recalls are free at Peugeot dealers and involve retorquing or replacing the connection. Verify with VIN that this has been completed on any car within this production window.