Toyota 2TZ-FE

The 2.4 four of the first Toyota Previa and Estima.

⚑ It is mounted flat, under the floor, at 75° from vertical, and driven from a shaft at the front — and that single fact governs every job on it. The alternator, power steering pump, air conditioning compressor and water pump are all driven by a shaft running forward from the engine to the nose of the van, through a gearbox Toyota called the supplementary drive.

So a failure anywhere in that chain presents as several ancillaries failing together, which reads as an electrical fault and is not. Anybody diagnosing a charging or steering complaint on a Previa needs to know the drive shaft exists before they start.

Access is the constraint on everything else. Routine work means going in from inside the vehicle, and jobs priced from a conventional layout will be wrong.

The supercharged 2TZ-FZE adds boost to the same engine and its supercharger is clutched, so a lack of power with no fault code is worth tracing to that clutch.