Toyota Sienna
Flagship fourth-generation hybrid with Dynamic Force technology. Extremely economical for a vehicle of this size (under 5 l/100 km in the Camry). Timing chain, no known weaknesses so far. The gold standard for hybrid reliability.
Sienna XL40 hybrid-only — no more gas, surprisingly good
245 hp system output, hybrid mandatory from 2021. Sounds boring, drives surprisingly well. 36 mpg in a minivan — that's the argument. No driving fun ambitions, but the most efficient Sienna ever.
Engine Weaknesses 6
The hybrid battery in the RAV4 XA50 with A25A-FXS sits under the rear seat and can be damaged by moisture. Blocked ventilation slots lead to battery overheating.
Symptoms: Hybrid warning light, reduced battery output, 'Check Hybrid System' message, in severe cases complete battery failure
The EGR system on the A25A-FXS tends to clog with deposits from approximately 130,000 km. The EGR cooler develops cracks and allows coolant to enter the EGR circuit.
Symptoms: Power loss; foul smell while driving; low coolant level; fault messages on the instrument cluster
The timing chain is considered a weak point on the A25A-FXS and should be inspected preventively at approximately 150,000 km. The frequent engine start/stop cycles in hybrid operation increase the load.
Symptoms: Rattle on start-up; metallic noise from the timing chain area; slightly rough idle
Toyota issued a TSB (T-TT-0614-20) for 2020 A25A-FXS engines: coolant leak at the housing or connector of the electric water pump.
Symptoms: Check engine light, coolant traces on the engine underside, dropping coolant level
In predominantly urban short-trip use the A25A-FXS hybrid engine does not reach operating temperature long enough to drive off fuel and condensation moisture from the oil. Oil dilution and increased bearing wear can result.
Symptoms: Oil level rises instead of dropping, oil smells of petrol, engine oil becomes watery and cloudy, increased wear
The A25A-FXS shares the risk of oil loss at sealing surfaces with other Dynamic Force engines. Long-term data is still limited at high mileage — seals should be inspected thoroughly.
Symptoms: Dropping oil level, oil spots under the vehicle, faint burning smell
Vehicle Weaknesses 3
Multimedia system occasionally freezes, CarPlay/Android Auto disconnects. OTA updates improve but don't fully resolve.
Creaking noises from rear struts, especially in cold weather and over bumps.
Multiple reports of windshields cracking extensively from small chips. Toyota Safety Sense recalibration after replacement expensive.