A diagnostic check on a vehicle with a supercharger reveals low boost pressure. After verifying the bypass valve operates correctly, what mechanical check should you perform?

1. Check for exhaust gas leaks at the tailpipe muffler connection
2. Inspect the drive belt for wear or slippage, check the electromagnetic clutch operation, and inspect the rotor seals for wear
3. Measure the resistance of the oxygen sensor heating circuit
4. Verify the operation of the radiator cooling fan assembly