Disconnect the ignition coil pack connector
Inspect the coil pack for cracks, burns, or corrosion
Check the spark plug wires or coil-on-plug boots for damage
Use a multimeter to test primary resistance
Use a multimeter to test secondary resistance
Compare resistance readings to the manufacturer specifications
Check for power supply at the coil pack connector
Check for ground continuity at the coil pack connector
Use a spark tester to verify spark output
Swap the coil pack with a known good unit if available
Scan for diagnostic trouble codes with an OBD-II scanner
Clear codes and retest after repairs