The 2020 BMW Z4 (G29) shares its B48 2.0L turbo engine with the Toyota Supra, and while it's a solid platform overall, the early production units have seen some catastrophic engine failures and a handful of electrical gremlins that can ground an otherwise fun roadster.
B48 Engine Internal Failure (Piston Ring Land Fracture)
Rare · high severity
Typical onset: 15,000-50,000 mi
Symptoms: Excessive oil consumption (quart per 1,000 miles or worse), White or blue smoke from exhaust under load, Misfires, rough idle, loss of power, Check engine light with low compression codes
Fix: Complete engine rebuild or short block replacement. This is typically a piston ring land fracture on cylinder 2 or 3, sometimes related to pre-ignition or manufacturing defect. BMW has extended warranty coverage on some VINs. Expect 18-24 labor hours for short block swap, more for full rebuild.
Estimated cost: $8,000-15,000
8-Speed ZF Transmission Oil Cooler Line Leak
Occasional · medium severity
Typical onset: 30,000-70,000 mi
Symptoms: Transmission fluid puddle under vehicle, driver's side, Low transmission fluid warning on iDrive, Harsh shifting or slipping if fluid level drops significantly
Fix: Replace the transmission oil cooler lines where they connect at the cooler or transmission housing. Often corroded fittings or chafed lines. 3-4 hours labor, need to drop undertray and possibly exhaust heat shield.
Estimated cost: $600-1,200
Rear Camera Failure / Back-Up Camera Intermittent
Common · low severity
Symptoms: Black screen or 'camera unavailable' message when shifting to reverse, Intermittent function, works after car sits or restarts, May trigger parking assist faults
Fix: Usually a camera module replacement behind the trunk handle area. Occasionally a wiring harness chafe or moisture intrusion issue. BMW issued a recall (NHTSA 21V-868) for some VINs. 1.5-2 hours labor if just the camera, more if harness repair needed.
Estimated cost: $400-900
Headlight Condensation and LED Driver Failure
Occasional · medium severity
Symptoms: Moisture or condensation inside headlight lens, Headlight out warning, typically one side, Flickering or dim headlight, adaptive lighting malfunction
Fix: Early production units had inadequate vent sealing. BMW issued TSB and recall coverage for some builds (NHTSA 20V-709, 21V-096). Complete headlight assembly replacement usually required—these are expensive adaptive LED units. 2-3 hours labor per side including coding.
Estimated cost: $1,800-3,500
Fuel Tank Vent Valve / Evaporative Emissions Fault
Occasional · low severity
Typical onset: 20,000-60,000 mi
Symptoms: Check engine light with EVAP leak codes (P0442, P0456), Difficulty fueling, pump clicks off repeatedly, Fuel smell near rear of vehicle
Fix: Vent valve on fuel tank or canister purge valve failure. BMW recall 21V-253 addresses some tank assemblies. If just the purge valve, 1-1.5 hours; full tank vent valve requires tank drop, 4-5 hours.
Estimated cost: $350-1,400
Starter Relay Intermittent No-Start
Rare · high severity
Symptoms: No-crank, no-start condition—electronics power on but starter doesn't engage, Clicking from under hood or no sound at all, Intermittent, may start fine after sitting or multiple key cycles
Fix: Faulty starter relay in fuse box under hood or main relay in junction box. BMW recall 22V-835 covers some production runs. Relay replacement is straightforward (0.5-1 hour), but diagnosis can add time if intermittent.
Estimated cost: $200-500
Owner tips
Check oil level every 1,000 miles in the first year of ownership—early detection of consumption issues can save an engine
Use TOP TIER gas and avoid constant low-RPM lugging; B48 responds well to Italian tune-ups to keep intake valves clean
Inspect transmission cooler lines annually if you live in salt-belt states—corrosion accelerates on these fittings
Keep the soft-top mechanism clean and lubricated per BMW schedule; micro-switch failures are expensive
Fun platform with Toyota co-engineering, but 2020-2021 models carry engine failure risk—insist on comprehensive pre-purchase inspection with compression/leak-down test and documented oil consumption history, or buy CPO with warranty extension.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.
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BMW of North America, LLC (BMW) is recalling certain 2019-2021 BMW 330i, 2019-2022 BMW Z4, 2020-2022 BMW 530i, X3, X4, Toyota Supra, 2021-2022 BMW 430i, 430i Convertible, and 2022 BMW 230i vehicles. The engine starter relay may corrode, causing the relay to overheat and short circuit.
Consequence: A short circuit in the starter relay may increase the risk of a fire.
Remedy: Owners are advised to park their vehicles outside and away from structures until the remedy is complete. Dealers will replace the engine starter, free of charge. Owner notification letters were mailed February 6, 2026. Owners may contact BMW customer service at 1-800-525-7417. Vehicle Identification Numbers (VINs) involved in this recall will be searchable on NHTSA.gov beginning November 14, 2025.
ENGINE · 21V598000
2021-08-02
BMW of North America, LLC (BMW) is recalling certain 2020 M340i, M340i xDrive, 540i, 540i xDrive, X3 M40i, 2020-2021 X4 M40i, 745Le xDrive, 2019-2021 Z4 M40i, and 2020-2021 Toyota Supra vehicles. During engine start, the engine management software may cause loss of braking assist. Full mechanical braking (without assist) remains available.
Consequence: Loss of braking assist can increase the risk of a crash.
Remedy: Dealers will update the engine management software, free of charge. Owner notification letters were mailed on September 17, 2021. Owners may contact BMW customer service at 1-800-525-7417.
BMW of North America, LLC (BMW) is recalling certain 2020-2021 Z4 and 2020-2021 Toyota Supra vehicles. The weld between the fuel tank halves may have been insufficiently welded, causing the weld to fail.
Consequence: The failed weld may allow fuel to leak, increasing the risk of a fire in the presence of an ignition source.
Remedy: BMW will notify owners, and dealers will replace the fuel tank, free of charge. The recall began December 18, 2020. Owners may contact BMW customer service at 1-800-525-7417 or Toyota customer service at 1-888-270-9371.
EXTERIOR LIGHTING:HEADLIGHTS · 20V516000
2020-08-27
BMW of North America, LLC (BMW) is recalling certain 2019-2020 Z4 sDrive30i, Z4 M40i and 2020 Toyota Supra vehicles. The headlamps are able to be adjusted horizontally. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 108, "Lamps, Reflective Devices and Associated Equipment."
Consequence: Should the headlamps be adjusted horizontally, there could be increased glare and reduced visibility for oncoming drivers, or reduced visibility for the vehicle operator, thereby increasing the risk of a crash.
Remedy: BMW will notify owners, and dealers will inspect the headlamp vertical and horizontal adjustment plugs, correcting them as necessary, free of charge. The recall began December 23, 2020. BMW owners may contact BMW customer service at 1-800-525-7417 or Toyota owners may contact Toyota customer service at 1-888-270-9371.
EXTERIOR LIGHTING:HEADLIGHTS · 19V850000
2019-11-27
BMW of North America, LLC (BMW) is recalling certain 2020 Z4 M40i, Z4 sDrive30i, 330i and 330i xDrive vehicles as well as 2020 Toyota Supra vehicles. The headlight control units may fail causing a loss of one or both of the headlights.
Consequence: Headlight failure can reduce the driver's visibility, increasing the risk of a crash.
Remedy: BMW will notify owners, and dealers will replace the headlight control units, free of charge. The recall is expected to begin January 17, 2020. Owners may contact BMW customer service at 1-800-525-7417 or Toyota customer service at 1-888-270-9371.
BACK OVER PREVENTION: SENSING SYSTEM: CAMERA · 19V684000
2019-09-27
BMW of North America, LLC (BMW) is recalling certain 2018 540d, 2018-2020 530i, 530i xDrive, 540i, 540i xDrive, M550i xDrive, M5, 530e, 530e xDrive, X3 sDrive, X3 xDrive, X3 M40i, X3 M, and 2019-2020 X4 xDrive, X4 M40i, X4 M, X7 xDrive, X7 M50i, 740Li, 740Li xDrive, 750Li, 750Li xDrive, 8 Series Convertible and Coupe 840i, 840i xDrive, M850i xDrive, X5 sDrive, X5 xDrive, X5 M50i, X6 xDrive, X6 M50i, 330i, 330i xDrive, M340i, M340i xDrive, Z4 sDrive, Z4 M40i, 740Le xDrive and 745Le xDrive, 2018-2019 640i xDrive Gran Turismo and Rolls-Royce Phantom, 2019 M850i xDrive Gran Coupe and Rolls-Royce Cullinan and 2020 Toyota Supra vehicles.
The back-up camera and display settings can be adjusted such that the rear view image is no longer visible and the system will retain that setting the next time the vehicle is placed in reverse. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard (FMVSS) number 111, "Rearview Mirrors."
Consequence: The lack of an image in the back-up camera display increases the risk of a crash.
Remedy: BMW will notify owners, and dealers will update the back-up camera software, free of charge. The recall began November 8, 2019. Owners may contact BMW customer service at 1-800-525-7417 or Rolls-Royce at 1-877-877-3735. Toyota owners may contact Toyota customer service at 1-888-270-9371.
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