IsItAGoodCar
Reliability Guide

Common Problems with the
2020 BMW 4 Series (G22/G23/G26)

Launched in June 2020, the second 4 Series split the old F32 range into G22 coupe, G23 convertible and G26 Gran Coupe bodies on the CLAR rear-drive architecture shared with the G20 3 Series. UK engines were the B48 420i, B58 430i and M440i plus B47 and B57 diesel 420d and 430d.

What changed for 2020

  • •Much larger vertical grille, the most divisive BMW face of its generation
  • •Gran Coupe body adopted the G26 code associated with the i4 electric model
  • •Curved-display-free but fully digital cockpit with the iDrive 7 system

Common MOT watch-outs

  • !Exterior lighting and sensor damage on low front splitters
  • !DPF and EGR advisories on diesel examples used for short trips
  • !Tyre wear and kerbed 18 to 20-inch wheels on M Sport cars
3
Known Issues
0
Serious
3
Moderate
0
Minor

All Known Issues

Radar Sensor Misalignment

ModerateElectrics & Electronics

The front radar sensor located in the large kidney grille is vulnerable to even minor "nudges", which can knock it out of alignment and disable the cruise control and safety systems.

Est. Repair Cost: £200–£500
Warning Signs:

"Driver Assistance Restricted" warning on dash, Active Cruise Control refusing to engage, Emergency braking system warnings

What to Inspect:
  • Inspect the radar sensor for any visible cracks or impact marks
  • Ask for a diagnostic report if any assistance warnings are present
  • Check if the sensor bracket is loose
Verified by IsItAGoodCar Research Team

Coolant Loss (B58 Engine)

ModerateCooling System

The M440i can suffer from slow coolant loss, often from the expansion tank cap or a minor weep from the water pump or turbo cooling lines.

Est. Repair Cost: £50–£300
Warning Signs:

Low coolant warning on the iDrive, Sweet smell of coolant after a spirited drive, Dried white residue around the expansion tank cap

What to Inspect:
  • Check the coolant level when the engine is stone cold
  • Inspect the expansion tank for hairline cracks
  • Look for any signs of blue or green residue on the front of the engine
Verified by IsItAGoodCar Research Team

Active Grille Shutter Motor Failure

ModerateCooling System

The motorised flaps behind the front grilles can fail to open or close correctly, throwing an engine management light and affecting aerodynamics.

Est. Repair Cost: £300–£600
Warning Signs:

Check Engine Light (EML) with air flap codes, Flaps stuck in one position, Fan running more than usual

What to Inspect:
  • Verify the shutters move during the vehicle's startup sequence
  • Check for any debris (leaves/stones) lodged in the mechanism
Verified by IsItAGoodCar Research Team

Buying Tips for 2020 BMW 4 Series (G22/G23/G26)

  • Check the grille and bumper mounting, as the large panels are easily damaged and costly to replace
  • Confirm the car has the driver assistance pack you want, since spec gaps between used examples are wide
2021–2023
Check a 2020 BMW 4 Series (G22/G23/G26) by Registration