BMW 740e G11

The KLE (Komfort-Lade-Elektronik) is the onboard charger that converts mains AC power to charge the high-voltage battery. It is the most commonly reported failure on BMW PHEVs including the 740e. Symptoms include 'Unable to charge' errors, a flashing red ring on the charging port, and 'Mains power too low' messages even on a verified-good supply. The module typically fails between 3 and 6 years of age, often regardless of mileage. BMW dealerships charge approximately €2,000-2,500 for replacement including coding. Independent specialists can source reconditioned units and complete the work for €1,500-1,800 total. Without a functioning KLE, the car cannot charge via plug and loses all electric driving capability, though it continues to function as a normal petrol vehicle. BMW has generally refused goodwill claims outside the standard warranty period.

All G11 7 Series models have standard air suspension on all four corners. The rubber air bladders degrade over time, developing slow leaks that cause a corner to sag overnight or within hours. Symptoms include a 'Chassis Function Limited' warning and visibly uneven ride height. OEM struts cost €900-1,200 per corner; with labor, expect €1,500-2,000 per strut at an independent specialist. Aftermarket options from Aerosus bring parts cost to around €400-900 per strut. The air compressor can also fail from overworking to compensate for leaking struts, adding €400-600 for the compressor unit plus labor. BMW extended the warranty on G11 air suspension to 8 years / 130,000 km in some markets. Front struts tend to fail before rears due to heat exposure from the engine bay.

The B48 engine's oil filter housing is plastic with a rubber gasket that degrades from repeated thermal cycling. This is one of the most common B48 issues, with multiple forum threads documenting failures between 80,000 and 120,000 km. Because the housing integrates an oil cooler with coolant passages, a crack can allow oil and coolant to mix, risking serious engine damage if left unaddressed. Symptoms include a burning oil smell, visible oil seepage around the intake manifold, or unexplained coolant loss. Gasket-only replacement at an independent shop costs approximately €400-600. If the housing itself has cracked, the complete unit plus labor runs €800-1,200. A class action lawsuit has been filed in the US regarding B48 oil filter housings, indicating the issue is widespread across the engine family.

The 740e's 9.2 kWh lithium-ion battery can degrade significantly over time, with some owners reporting range dropping from 30+ km to under 15 km after 5-7 years. Individual cell failures trigger drivetrain malfunction warnings and disable hybrid mode entirely. BMW warrants the HV battery for 8 years / 160,000 km in Europe with a 70% capacity guarantee. Outside warranty, cell module replacement costs approximately €5,000-7,000, while a complete battery pack can reach €8,000-10,000 at a BMW dealer. Independent specialists offer reconditioning for approximately 30-50% less than dealer pricing. Cars that sit uncharged for extended periods suffer accelerated degradation. For 2016-2018 production, battery cells are now 7-10 years old, making a health check essential before purchase.

The B48 uses an electric water pump integrated with the thermostat housing. The pump seal or bearing can fail suddenly, causing rapid coolant flow loss and engine overheating if not detected quickly. On the 740e, the PHEV system adds additional thermal management demands from battery cooling. The pump and thermostat assembly costs €300-500 for parts, with total repair running €600-900 at an independent specialist and €1,000-1,200 at a BMW dealer. Proactive replacement around 120,000 km is advisable. The B48 also has known coolant system weak points including a plastic vent line from the cylinder head that becomes brittle near the turbo and can snap, causing rapid coolant loss.

The SME (Battery Safety Module, integrated in the HV battery) and EME (Electric Motor Electronics) manage the hybrid drivetrain's high-voltage systems. If either module develops a fault, the HV contactors open and the car cannot use or charge the HV battery. Because the 740e has no conventional alternator (the electric motor acts as generator), SME/EME faults also cause the 12V battery to drain. Diagnostics require dealer-level BMW tools. Module replacement plus programming typically costs €2,500-7,000 depending on which unit is affected. This is a less common failure than the KLE or air suspension, but the cost impact is significant when it occurs.

BMW issued a global recall affecting approximately 575,000 vehicles worldwide, including G11 7 Series models manufactured between July 2020 and July 2022. Metal abrasion in the starter motor's magnetic switch can cause a short circuit, leading to overheating and a potential fire risk. While the 740e was phased out in 2019, any late-registered 740e or 740Le xDrive variants assembled after July 2020 may be affected. BMW replaces the starter free of charge under recall. If the recall has not been performed and the starter fails outside coverage, replacement costs €800-1,500.

The G11 7 Series has numerous electronic control modules (telematics, comfort access, gesture control, night vision) that can fail to enter sleep mode properly, draining the 12V auxiliary battery within days of parking. Normal parasitic draw should be 50-85 mA, but faulty modules can pull over 100 mA continuously. Common culprits include the TCU (telematics control unit) and comfort access sensors. Software updates frequently resolve the issue, but persistent cases require diagnosis and module replacement. The 12V AGM battery itself costs €200-300, plus €100-200 for diagnosis. Many 740e owners keep the car on a trickle charger when parked for more than a few days.