The air compressor should be inspected only when
- the parking brakes are released.
- the vehicle is parked on a level surface.
- the engine is off. ✓
- the engine is idling.
Answer: C. the engine is off.
The air compressor should be inspected only when the engine is off.
Why this is the answer
The handbook says the compressor is mounted on the engine and is driven by gears or a belt, and that it runs whenever the engine is running. That means an idling engine still has the compressor running. To inspect the compressor as a stopped component, the engine must be off. The passages do not make level ground or released parking brakes a condition for this inspection.
Why the other answers are wrong
- A. the parking brakes are released. — Nothing in the handbook ties compressor inspection to releasing the parking brakes.
- B. the vehicle is parked on a level surface. — The passages do not say the vehicle must be parked on a level surface for compressor inspection.
- D. the engine is idling. — With the engine idling the compressor is still running, so that is not when you would inspect it.
Remember it
If the engine is turning, the compressor is turning; inspect it with the engine stopped.
Official handbook: ICBC Driving Commercial Vehicles, 8 Air brakes – Compressor, p. 150