Faulty ignition coil with a failed secondary winding; Worn or fouled spark plug increasing secondary circuit resistance; Damaged or corroded coil connector and secondary wiring; Moisture or oil intrusion into the spark plug well shorting the coil; Cracked coil boot allowing spark to arc to ground; PCM driver or feedback circuit fault (less common)

DTC codes / Mazda codes / P1365

P1365 · MazdaIgnition Coil Secondary Circuit

Q: What does code P1365 mean?

Ignition Coil Secondary Circuit. P1365 on Mazda vehicles indicates that the powertrain control module (PCM) has detected an abnormal condition in the secondary, high-voltage side of an ignition coil circuit. The PCM monitors the coil's firing feedback and flags this code when the secondary circuit does not produce the expected ignition event, which points to a coil, plug, or wiring fault rather than a fuel or air problem.

P1365 on Mazda vehicles indicates that the powertrain control module (PCM) has detected an abnormal condition in the secondary, high-voltage side of an ignition coil circuit. The PCM monitors the coil's firing feedback and flags this code when the secondary circuit does not produce the expected ignition event, which points to a coil, plug, or wiring fault rather than a fuel or air problem.

SystemPowertrain

Code typeMazda specific

SeverityMedium

Fix difficultyIntermediate

AreaIgnition system and misfire

Symptoms you may notice

Check engine light illuminated, often with no other noticeable symptoms
Rough idle or a noticeable shake at stoplights
Engine misfire or hesitation under acceleration
Reduced power and poor fuel economy
A flashing check engine light in severe misfire cases
Hard starting or stalling on some Mazda models

Common causes, most likely first

Faulty ignition coil with a failed secondary winding
Worn or fouled spark plug increasing secondary circuit resistance
Damaged or corroded coil connector and secondary wiring
Moisture or oil intrusion into the spark plug well shorting the coil
Cracked coil boot allowing spark to arc to ground
PCM driver or feedback circuit fault (less common)

How to diagnose and fix it

Scan all modules and record freeze-frame data to confirm which cylinder is affected
Inspect the coil, boot, and spark plug well for oil, moisture, or carbon tracking
Swap the suspect coil to another cylinder and recheck to see if the misfire follows
Test the coil primary and secondary resistance with a multimeter against Mazda specs
Replace the spark plugs and any damaged coil boot or connector as needed
Replace the faulty ignition coil and clear the code, then verify with a road test
If the fault persists, check the coil control and feedback wiring back to the PCM

What P1365 really points to on Mazdas

A misfire that follows a swapped coil confirms the coil is at fault, while a misfire that stays on the same cylinder points to a plug, injector, or compression problem.
Oil leaking past the valve cover gasket into the spark plug well is a frequent hidden cause on older Mazda engines and ruins coils quickly.
P1365 can be set by a single failed ignition event during a cold start, so clearing the code and monitoring misfire counters is smarter than replacing parts immediately.
A flashing check engine light with P1365 means raw fuel is reaching the catalytic converter and the vehicle should not be driven until repaired.
Secondary ignition faults are often misdiagnosed as fuel delivery problems because the symptoms of a misfire are nearly identical.

Can I keep driving with P1365?

You can usually drive a short distance to a shop if the light is steady and the engine runs smoothly, but avoid hard acceleration and long trips. If the check engine light flashes or the engine shakes badly, stop driving to protect the catalytic converter and prevent further damage.

Tools that help

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