Toyota

Corolla, Auris, Avensis. Bulletproof unit; older 1ZZ versions could burn oil, which sometimes takes the catalyst and O2 sensors with it.

Avensis and RAV4 diesels. The early 2.2 had head gasket sins; otherwise classic diesel territory: DPF, EGR and injectors at high mileage.

RAV4 and Camry Hybrid powertrain. Faults are rare; C1201 is almost always an echo of something minor on the petrol engine side.