OBD-II Code P0359 — What It Means & How to Fix It

What Does This Error Mean?

P0359 means the PCM detected an electrical fault in the primary circuit of ignition coil I. Coil I is the 9th coil in the ignition firing order — found mainly on V10 and V12 engines. The primary circuit is the low-voltage side that the PCM triggers to fire the coil. Expect a rough idle, misfire, and reduced power alongside this code.

Affected Models

All 1996+ V10 and V12 engines with individual coil-on-plug ignition
Common in Ford F-250 and F-350 with the 6.8L Triton V10 engine
Common in Dodge Viper with the 8.0L and 8.4L V10 engines
Common in V12 European vehicles such as BMW and Mercedes-Benz
Less common — primarily affects large-displacement high-cylinder-count engines

Common Causes

Failed ignition coil I with an open or shorted primary winding
Damaged, abraded, or burned wiring in the coil I control harness
Corroded or loose harness connector at the coil I plug
Worn or fouled spark plug in the 9th firing cylinder stressing and damaging the coil
PCM coil driver fault on the coil I output channel (rare)

How to Fix It

Look up the firing order for your exact engine. Coil I is the 9th position in that firing order. On a Ford 6.8L V10, for example, the firing order is 1-6-5-10-2-7-3-8-4-9. Count to the 9th position to find which physical cylinder coil I controls.

V10 and V12 engines have complex firing orders. Do not guess. Use your service manual or a make-specific reference for the exact firing order before doing any work.
Inspect the coil I harness connector. Check for pushed-back terminals, corrosion, cracked plastic, or a connector not fully seated. Clean the connector with electrical contact cleaner and reseat it firmly.

On large V10 and V12 engines, some coils are buried deep in the valley or near the firewall where connectors are prone to heat damage and vibration loosening.
Do a coil swap test. Move coil I to a nearby cylinder of the same type and place that coil where coil I was. Clear all codes and drive. If P0359 follows the swapped coil, coil I is defective and needs replacement.

The swap test is the most reliable DIY method. If the code stays fixed on coil I position after the swap, the problem is in the wiring or PCM — not the coil itself.
Remove and inspect the spark plug for the coil I cylinder. Replace it if worn, fouled, or cracked. Always pair a new coil with a new spark plug on the same cylinder.

High-mileage V10 engines often have plugs that are extremely difficult to remove. Use penetrating oil and the proper socket size to avoid breaking the plug in the head.
Install a replacement coil in the coil I position. Reconnect the harness plug until it clicks securely. Clear all stored DTCs and road test with several acceleration cycles. Confirm no misfire codes return and P0359 is resolved.

If the code returns on a new coil, have a technician test the PCM driver signal with an oscilloscope. A recurring code on a new coil almost always points to the PCM.

When to Call a Professional

If swapping coil I moves the code to a different cylinder, the coil is bad and replacement is straightforward. If the code stays on the same cylinder after swapping, the wiring or PCM driver is at fault and needs professional diagnosis. Technicians can scope the PCM coil trigger signal to confirm PCM output. Diagnosis runs $80-$150 at most shops. Coil-on-plug replacement costs $30-$100 depending on the engine.

Frequently Asked Questions

What vehicles actually get a P0359 code?

P0359 is only possible on engines with 9 or more cylinders using individual coil-on-plug ignition. The most common examples are the Ford F-Series with the 6.8L Triton V10 and the Dodge Viper V10. V12 European vehicles — BMW 7-series, Mercedes S-Class, Jaguar — can also trigger it. If you have a 4-cylinder or 6-cylinder, you will never see this code.

Is it safe to drive with P0359?

Only for very short distances at low speed. A misfiring cylinder sends unburned fuel into the exhaust, which can quickly destroy the catalytic converter. If the check engine light is flashing rather than staying on steady, stop the vehicle right away and do not continue driving — the converter is being damaged in real time.

Are coil-on-plug coils for V10 engines expensive?

They cost more than coils for a standard V8. Expect to pay $40-$100 per coil for a Ford Triton V10 or Dodge Viper V10. OEM Ford coils are well-regarded and often worth the price. Some high-quality aftermarket options are available but vary widely in reliability, so stick to reputable brands.