Ignition Coil I Primary/Secondary Circuit Malfunction (Cylinder 9)
What does P0359 mean?
The P0359 code means the vehicle's onboard diagnostic system has detected: Ignition Coil I Primary/Secondary Circuit Malfunction (Cylinder 9). This is a moderate severity code.
Common Symptoms
- Engine misfire on cylinder 9
- Rough idle on V10 engine
- Check Engine Light illuminated or flashing
- Reduced power
- Exhaust has fuel smell
Probable Causes (Ranked by Likelihood)
- Faulty ignition coil on cylinder 9 Very High
- Worn or fouled spark plug on cylinder 9 High
- Damaged coil connector or wiring High
- PCM coil driver circuit failure for cylinder 9 Moderate
- Coil boot deterioration from heat exposure Low
Step-by-Step Diagnostic Procedure
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Swap cylinder 9 ignition coil with another cylinder and clear codes to test
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Inspect the spark plug on cylinder 9 for wear, fouling, or damage
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Measure coil resistance and compare to specification
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Check the coil connector and boot for heat damage or carbon tracking
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Test PCM coil driver signal at the connector
Frequently Asked Questions
Can I drive with code P0359?
You can drive short distances. On a V10 engine, losing one cylinder still leaves nine working, but the misfire should be repaired to protect the exhaust system.
What vehicles have a cylinder 9?
Only V10 engines have a cylinder 9. The most common are the Ford Triton 6.8L V10 found in F-250/F-350 trucks and E-Series vans, and the Dodge Viper V10.
Are V10 spark plugs more difficult to change?
Ford V10 engines are known for spark plug issues, including plugs that can break during removal due to carbon buildup in the threads. Using anti-seize compound during installation and changing plugs at recommended intervals helps prevent this.