Faulty ignition coil 'I' (primary or secondary winding failure); Worn or damaged spark plug or spark plug boot; Open or shorted wiring in the coil's primary circuit; Corroded or loose electrical connector at the coil; Failed ignition control module or driver circuit inside the ECM; Poor engine ground connection affecting coil operation; Aftermarket or incorrect coil installed previously

DTC codes / P03xx · Ignition system and misfire / P0359

P0359Ignition Coil 'I' Primary/Secondary Circuit

Q: What does code P0359 mean?

Ignition Coil 'I' Primary/Secondary Circuit. P0359 indicates that the engine control module (ECM) has detected an abnormal condition in the primary or secondary circuit of ignition coil 'I', which is typically the ninth coil in the firing order on engines with multiple coils. The ECM monitors the coil's electrical behavior and sets this code when the circuit does not respond as expected, often due to an open, short, or excessive resistance.

P0359 indicates that the engine control module (ECM) has detected an abnormal condition in the primary or secondary circuit of ignition coil 'I', which is typically the ninth coil in the firing order on engines with multiple coils. The ECM monitors the coil's electrical behavior and sets this code when the circuit does not respond as expected, often due to an open, short, or excessive resistance.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaIgnition system and misfire

Symptoms you may notice

Illuminated check engine light, often with no other noticeable symptoms
Engine misfire, especially under load or acceleration
Rough idle or shaking felt through the steering wheel and seats
Reduced engine power and poor fuel economy
Occasional stalling or difficulty starting
A flashing check engine light if the misfire is severe enough to damage the catalytic converter

Common causes, most likely first

Faulty ignition coil 'I' (primary or secondary winding failure)
Worn or damaged spark plug or spark plug boot
Open or shorted wiring in the coil's primary circuit
Corroded or loose electrical connector at the coil
Failed ignition control module or driver circuit inside the ECM
Poor engine ground connection affecting coil operation
Aftermarket or incorrect coil installed previously

How to diagnose and fix it

Perform a visual inspection of coil 'I', its connector, and wiring for damage or corrosion
Swap coil 'I' with a known-good coil from another cylinder and see if the code follows the coil
Test the primary and secondary resistance of the coil with a multimeter and compare to specifications
Check for spark at the affected cylinder using a spark tester
Inspect the spark plug and replace if worn or fouled
Test the wiring continuity and voltage supply to the coil connector
If all else checks out, diagnose the ECM driver circuit or replace the ECM as a last resort

Coil 'I' Circuit Quirks and Misdiagnosis Traps

A P0359 can be set by a faulty spark plug or boot that causes the coil to work harder, so always inspect the plug before condemning the coil.
On some engines, coil 'I' is not physically labeled; consult the firing order diagram to identify the correct coil.
Intermittent wiring faults often set P0359 only under certain conditions like vibration or heat, so wiggle-test the harness while monitoring live data.
A weak battery or charging system issue can cause multiple coil codes including P0359, so check system voltage first.
Replacing the coil without addressing a shorted driver in the ECM will lead to repeated coil failures and the same code returning.

Can I keep driving with P0359?

Driving with P0359 is possible but not recommended because a persistent misfire can overheat and damage the catalytic converter. Avoid heavy acceleration and have the fault diagnosed promptly; if the check engine light is flashing, stop driving and seek immediate repair.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.