Ignition Coil Resistance Test (4.2L & 5.9L)
- Remove primary and secondary leads from ignition coil. Using ohmmeter, check primary resistance between (positive) and (negative) terminals of coil. See IGNITION COIL RESISTANCE SPECIFICATIONS (4.2L & 5.9L) table.
- Check secondary resistance between center tower and either (positive) or (negative) terminals of coil. See IGNITION COIL RESISTANCE SPECIFICATIONS (4.2L & 5.9L) table. Replace coil if readings are not within specification.
IGNITION COIL RESISTANCE SPECIFICATIONS (4.2L & 5.9L)
| Application | Ohms | |
|---|---|---|
| Primary Resistance | ||
| At 75°F (24°C) | 1.13-1.23 | |
| At 200°F (93°C) | 1.5 | |
| Secondary Resistance | ||
| At 75°F (24°C) | 7700-9300 | |
| At 200°F (93°C) | 12,000 | |