Toyota M15A-FKS / M15A-FXE

Toyota's 1.5 Dynamic Force three-cylinder — in the Corolla, Yaris and Aygo X, and as the M15A-FXE the petrol half of their hybrids.

⚑ It is not Suzuki's M15A, which is a 1.5 FOUR, and the two are unrelated engines from unrelated companies that happen to have chosen the same three characters. This catalogue aliased one to the other for a day — both petrol, both 1.5, and their production spans overlap, so nothing but the marque separates them. Count the cylinders.

It is a very high compression ratio engine — around 13:1 — running a long stroke and a fast burn, which is where its efficiency comes from and why it is more sensitive to fuel quality and to carbon than an older Toyota four.

A three-cylinder is not inherently balanced, so it carries a balance shaft and vibrates more at idle than the fours it replaced. An owner reporting shake at a stop is very often describing normal behaviour, and establishing that before chasing mounts saves a day.

The M15A-FXE in the hybrids runs the Atkinson cycle inside a hybrid control strategy: lower output, different valve timing, and start, charge and idle complaints on one belong to the system rather than to the engine.

It is too new for a settled long-term record. What can be said comes from the design: it is chain-driven, it is port- and direct-injected together, and Toyota's own interval is what protects it.