On the Pennsylvania CDL air-brake check, during pre-trip, when checking the air system, you turn the key on but do not start the engine. Pressure is at full and brakes are released. You time the static leak rate. What value passes a single vehicle?

1. Less than 5 psi per minute
2. No more than 2 psi per minute
3. No more than 10 psi per minute
4. No more than 4 psi per minute