Toyota M20A (Dynamic Force 2.0)

The 2.0-litre Dynamic Force four — the A25A's smaller sibling, sharing its architecture and not its block — in the Corolla, C-HR, Corolla Cross, and the RAV4 and Camry of markets that tax the 2.5.

Everything that makes the 2.5 interesting is here: both port and direct injection, a very high compression ratio, variable cooling and an unusually high thermal efficiency. The dual-injection arrangement is the diagnostically relevant part, because it means the intake-valve carbon problem that afflicts direct-injection-only engines largely does not occur — the port injectors wash the valves. A rough-running complaint on one of these should not be attributed to carbon by analogy with a European direct-injection four.

The suffix says which car it is in and it is not cosmetic. M20A-FKS is the plain petrol, M20A-FXS the hybrid's Atkinson-cycle version, and the hybrid runs a different cycle, a different compression ratio and a different control strategy. A driveability complaint on an FXS is a question about the hybrid system at least as often as about the engine.

Being recent, its long-term failure patterns are not established, which is worth stating rather than filling with speculation. The systems generating faults so far are the ones carrying the most sensors: variable cooling, the exhaust-gas recirculation circuit, and on hybrids the interaction between engine control and the hybrid strategy.