Toyota GR Yaris

The Aisin 6-speed manual gearbox can develop crunching on 1st-to-2nd and 2nd-to-3rd shifts, particularly when cold. Some early 2020 Track Edition models had issues at just 600 km where synchronization rings wore prematurely. Toyota replaced affected gearboxes under warranty for cars in a certain VIN range. The gearbox is rated for 450 Nm (336 lb-ft) at flywheel - beyond this, fifth gear synchro and sleeve fail quickly. Gear changes improve when oil is changed around 10,000 km. A DIY fix involves adjusting the gear shift cable linkage. Toyota dealers should address this under warranty if within coverage period. Never rush cold shifts.

The GR Yaris windscreen is notably thin due to weight-saving, and owners report chips turning into full cracks within seconds at moderate speeds. A small chip "not much bigger than the tip of a ballpoint pen" can crack the screen 30 seconds later at just 50 km/h. Toyota quoted €1,000 for replacement in some markets, though insurance typically covers it (€25-90 with coverage). The plastic lower grille is fragile and costs €400-500 to replace because it forms the main bumper structure. Debris passing through the large grille mesh can damage the intercooler behind it, an even costlier repair. Many owners install protective mesh (€150) or full PPF (€1,000-1,500 for front end) to prevent damage.

A known issue where the boost pressure sensor/solenoid fails, resulting in loss of turbo boost power. Specialists have seen this multiple times and recognize it immediately. Symptoms include overboost fault typically in 1st gear when launching or setting off quickly, or the ECU requesting less boost as protection. The P010515 fault code indicates overboost. Earlier production cars are more affected - Toyota appears to have addressed this in later builds. Quick sensor replacement solves the issue. Also check all rubber hoses to the airbox, particularly those controlling the airbox flap, as a disconnected hose can cause the ECU to cap boost at around 0.9 bar.

The GR Yaris has "very cheap plastic and little to no sound deadening" leading to widespread rattle complaints. Common sources: A-pillar trim (even when sound appears to come from dash speakers), glovebox lid moving 2-3mm when shut, driver door handle trim buzzing, rear quarter panel vibration at 2,700 rpm, and sensor housing behind rearview mirror. One dealer found wiring loom routing issues where the harness was pinched by the dash - Toyota requires photos of this specific issue for warranty claims. DIY fixes include thick foam tape on A-pillar edges, felt tape on mirror sensor housing, and fastening unused rear seatbelts. Toyota dealers have removed entire dashboards to add padding. The scuttle plate being in compression has also caused rattles. Gets worse after a few thousand miles.

A small number of owners have experienced clutch failure at relatively low mileage - one case at just 14,000 km (2,000 miles) requiring a second standard clutch replacement. The GR Yaris suffers from poor pressure plate response time - the spool down from pressing the clutch to the pressure plate actually releasing the clutch disk is too slow. Toyota initially refused warranty replacement claiming hard driving, but after owner contacted Toyota Japan during an eight-week dispute, the clutch was replaced under warranty. OEM clutch costs €2,057.82 and flywheel €863.59 including VAT, totaling approximately €2,921 for parts alone. Aftermarket options like Helix or Pumaspeed kits cost €800-1,400 plus €590 labor. This appears to affect only a minority of cars but is worth monitoring.

During extended track sessions, the electronically controlled multi-plate clutch in the transfer case can overheat, causing the system to disconnect the rear axle for protection. This isn't a failure - it's electronic protection preventing damage - but ends track use for that session. High load at low speed is worst, such as gymkhana or parking lot antics. The transfer case itself gets hot but has no temperature feedback to the 4WD controller; only the ITCC unit monitors temperature. Factory GR Yaris already has cooler line location prep that just needs to be connected. Toyota recommends changing transmission, transfer case, and differential fluids at half the specified distance or after track use. Some tuned cars with 255-265mm width tires have broken transfer case housings. Transfer case oil seal/bearing failures have been reported around 68,000 km where the bearing cage (plastic) breaks into pieces.

A small number of G16E-GTS engines have experienced catastrophic piston failure where pistons disintegrate, punching holes through the block. The suspected cause is Low Speed Pre-Ignition (LSPI) where fuel/oil droplets auto-ignite. This appears to be related to oil control issues that worsen with age and kilometers. Toyota has superseded pistons, block, valve springs, valves, and cams across Gen 2 and Gen 3 engines, using different piston part numbers for each generation. Manufacturing tolerances mean some engines are more affected than others. Most failures appear on higher-mileage engines or significantly modified cars. Stock engines rarely fail - many forum members question how many truly stock GR Yaris engines have failed with verifiable sources. The engine is overbuilt and tunable to 400-500hp on stock internals. WRC Yaris cars push 450hp on the same engine. One warranty claim was denied after Toyota detected the vehicle drifting at 173 km/h with engine overheating to 120°C.

The factory valve springs are a known weak point on the G16E-GTS engine, particularly for track use or tuned cars running high RPM. The GR86 and GR Yaris share this valve train weakness - the rocker arms have nothing to prevent them from dislodging. Toyota has been aware of this for approximately 5 years but hasn't upgraded the factory valve train. Up to stock redline of 7,000 rpm, upgraded valve spring kits from Kelford/Lamspeed address this issue. The Kelford KVS264 kit costs approximately €800-1,200 installed and supports factory or performance camshafts. For extreme builds (65 psi, 11,000 RPM), the KVS264-X extreme kit is available. This is primarily a concern for track-focused or heavily tuned cars, not stock street-driven examples.