2020 Chevrolet Onix Problems: 4 Known Issues

On the 2020 Chevrolet Onix, shortly after the second-generation Onix launched in Brazil, GM recalled 19,055 Onix Plus model-year 2020 sedans (produced April 29 to November 6, 2019, chassis LG100091-LG139164) because a faulty engine control module calibration on the new 1.0 turbo three-cylinder could cause abnormal pressure and temperature in the combustion chamber under certain conditions of atmospheric pressure, humidity and fuel composition. The resulting pre-ignition could break pistons, connecting rods or even the engine block, letting hot oil spray onto exhaust components and ignite. At least one vehicle fire was reported in Brazil's Northeast and another occurred at the Gravataí factory, and videos of burning units pressured Procon-SP to notify GM before the recall was formalized in November 2019. Some owners subsequently reported reduced power after the recalibration.

On the 2020-2024 Chevrolet Onix, the second-generation Onix and Onix Plus 1.0 turbo (CSS Prime three-cylinder, introduced 2019 for MY2020) use a timing belt that runs immersed in engine oil. GM rates the belt for 240,000 km or 15 years, but Brazilian owners, mechanics and the automotive press have documented widespread premature degradation and outright belt failures between roughly 50,000 and 100,000 km — sometimes under 50,000 km. Oil that does not meet the required Dexos specification (0W-20 for naturally aspirated, 5W-30 for turbo), extended oil-change intervals, sludge or contaminated fuel attacks the belt rubber, which dries, sheds teeth and disintegrates; debris can also clog the oil pickup. When the belt snaps on this interference engine, pistons strike valves and the repair can involve a full cylinder head rebuild or engine replacement, easily exceeding R$10,000. The problem became serious enough that GM South America announced a service action to inspect and replace belts on affected Onix, Onix Plus, Tracker and Montana units, while many warranty claims were initially denied over oil-spec documentation.

On the 2020-2024 Chevrolet Onix, a chronic and widely reported air-conditioning fault affects second-generation Onix and Onix Plus models (2020+), with similar AC complaints also common on the first generation. The system cools normally for the first few minutes after start-up, then begins blowing warm air even though the compressor stays engaged and refrigerant pressure reads normal; cooling temporarily returns after the car is shut off and restarted. Brazilian AC specialists traced the recurring fault to the expansion valve jamming, which drastically reduces suction in the circuit. Because gauge pressures look normal, shops frequently misdiagnose the problem and replace the compressor (around R$2,000) without fixing anything. The original valve design is considered flawed, so replacement with the same OEM part can fail again; some specialists fit an alternative valve for durability. Complaints about the Onix AC blowing hot air and 'vinegar smell' from the vents are among the most common entries for the model on Reclame Aqui and the Opinautos defect database.

On the 2020-2023 Chevrolet Onix, owners of 2020-2023 Onix and Onix Plus report recurring failures of the MyLink infotainment system: the screen freezes on the boot logo or with a frozen image, flickers or goes black, the touchscreen and hard buttons stop responding, and the unit reboots randomly. A separate but related software defect causes wireless Android Auto to disconnect intermittently with a 'Wi-Fi interference' message. Because the reversing camera displays through the head unit, a frozen or black screen also takes out the camera image. Complaints are concentrated on Reclame Aqui and the Clube do Onix owner forum across MY2020-2023 vehicles, and GM's fix is a software update applied via official USB pendrive at dealerships — some out-of-warranty owners report being charged for the update, which itself generated complaints.