Failed ignition coil on cylinder 6 (open primary or secondary winding); Damaged or corroded electrical connector at the cylinder 6 coil; Broken, chafed, or open wire in the coil trigger circuit between the ECM and coil; Poor ground connection for the ignition coil circuit; Faulty ECM driver for the cylinder 6 coil (rare but possible); Oil or coolant contamination fouling the coil boot or connector

DTC codes / Jaguar codes / P1366

P1366 · JaguarIgnition Coil Cylinder 6 No Activation

Q: What does code P1366 mean?

Ignition Coil Cylinder 6 No Activation. P1366 on a Jaguar means the engine control module (ECM) commanded the ignition coil for cylinder 6 to fire but detected no electrical activation or feedback from that coil circuit. The computer sees an open or inactive coil primary circuit on cylinder 6, so that cylinder is not being ignited properly.

P1366 on a Jaguar means the engine control module (ECM) commanded the ignition coil for cylinder 6 to fire but detected no electrical activation or feedback from that coil circuit. The computer sees an open or inactive coil primary circuit on cylinder 6, so that cylinder is not being ignited properly.

SystemPowertrain

Code typeJaguar specific

SeverityMedium

Fix difficultyIntermediate

AreaIgnition system and misfire

Symptoms you may notice

Check engine light illuminated, often with no other noticeable symptoms at first
Rough idle or a noticeable shake, especially when the engine is cold
Misfire sensation or hesitation during acceleration
Reduced engine power or limp mode on some models
Poor fuel economy and a strong fuel smell from the exhaust
Occasional flashing check engine light under load if the misfire is severe

Common causes, most likely first

Failed ignition coil on cylinder 6 (open primary or secondary winding)
Damaged or corroded electrical connector at the cylinder 6 coil
Broken, chafed, or open wire in the coil trigger circuit between the ECM and coil
Poor ground connection for the ignition coil circuit
Faulty ECM driver for the cylinder 6 coil (rare but possible)
Oil or coolant contamination fouling the coil boot or connector

How to diagnose and fix it

Scan all modules for stored and pending codes, then clear and road-test to confirm P1366 returns
Inspect the cylinder 6 ignition coil connector and wiring for corrosion, looseness, or chafing
Swap the cylinder 6 coil with a known-good coil from another cylinder and see if the misfire moves
Measure resistance of the cylinder 6 coil primary and secondary windings and compare with a good coil
Check for battery voltage and a good ground at the coil connector with the key on
Perform a spark test or use an oscilloscope to confirm the ECM trigger signal at the coil
If the coil and wiring test good, check the ECM driver circuit and repair or replace as needed

Why cylinder 6 coil codes mislead

A P1366 can be set by a coil that still sparks weakly at idle but fails under load, so a simple spark test may pass while the coil is still bad.
Jaguar coil connectors are prone to heat damage and brittle plastic, so a coil that tests fine on the bench can still cause this code through a poor connection.
Swapping coils between cylinders is the fastest way to confirm a coil fault, but you must clear the code and recheck because the ECM may not immediately re-enable the cylinder.
A misfire on cylinder 6 can be caused by a leaking injector or low compression, which will not set P1366 but can mimic the same driveability symptoms and lead to unnecessary coil replacement.
On some Jaguar models, the coil wiring harness runs close to hot exhaust components, so inspect for melted insulation before condemning the coil or ECM.

Can I keep driving with P1366?

You can usually drive short distances to a repair shop, but avoid heavy acceleration and prolonged driving because unburned fuel can overheat the catalytic converter. If the check engine light is flashing, stop driving and have the vehicle towed.

Tools that help

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