Faulty ignition coil 'G' with a failed secondary winding (open or shorted); Worn or damaged spark plug or spark plug boot on the affected cylinder; Corroded, loose, or damaged electrical connector at the coil; Damaged wiring in the secondary circuit, such as a chafed or broken wire; Poor ground connection for the ignition coil or engine block; Powertrain control module (PCM) internal fault, though this is rare; Aftermarket or incorrect coil installed that does not meet specifications

DTC codes / P23xx · Ignition system and misfire / P2320

P2320Ignition Coil 'G' Secondary Circuit

Q: What does code P2320 mean?

Ignition Coil 'G' Secondary Circuit. P2320 indicates that the powertrain control module has detected a fault in the secondary circuit of ignition coil 'G', which is the high-voltage side that fires the spark plug. The computer monitors the coil's secondary winding for expected electrical behavior and sets this code when the signal falls outside the normal range, often due to an open or shorted winding or a faulty connection.

P2320 indicates that the powertrain control module has detected a fault in the secondary circuit of ignition coil 'G', which is the high-voltage side that fires the spark plug. The computer monitors the coil's secondary winding for expected electrical behavior and sets this code when the signal falls outside the normal range, often due to an open or shorted winding or a faulty connection.

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 or rough running, especially under acceleration or load
Noticeable loss of power or hesitation during acceleration
Shaking or vibration from the engine, particularly at idle
Worse fuel economy than usual due to incomplete combustion
In some cases, a flashing check engine light if the misfire is severe enough to damage the catalytic converter

Common causes, most likely first

Faulty ignition coil 'G' with a failed secondary winding (open or shorted)
Worn or damaged spark plug or spark plug boot on the affected cylinder
Corroded, loose, or damaged electrical connector at the coil
Damaged wiring in the secondary circuit, such as a chafed or broken wire
Poor ground connection for the ignition coil or engine block
Powertrain control module (PCM) internal fault, though this is rare
Aftermarket or incorrect coil installed that does not meet specifications

How to diagnose and fix it

Perform a visual inspection of ignition coil 'G', its connector, and the spark plug boot for cracks, corrosion, or damage
Swap ignition coil 'G' with a known-good coil from another cylinder and see if the misfire or code follows the coil
Use a spark tester or oscilloscope to check for strong, consistent spark on the affected cylinder
Measure the resistance of the secondary winding with a multimeter and compare to the manufacturer's specification
Inspect the spark plug and replace it if worn, fouled, or damaged, and check the plug gap
Check the wiring harness for continuity and shorts between the coil connector and the PCM, repairing as needed
If all else checks out, replace ignition coil 'G' with a quality OEM or equivalent part and clear the code

Don't assume the coil is always at fault

A misfire code for a specific coil often results from a worn spark plug or a failing boot rather than the coil itself, so always inspect the plug and boot first.
Swapping the coil to a different cylinder is the quickest way to confirm whether the coil is truly defective or if the problem lies elsewhere in the circuit.
Corrosion or a loose connector at the coil can mimic a failed coil, and simply cleaning and reseating the connector may resolve the issue.
The PCM may set P2320 even when the coil still produces spark under light load, because the secondary circuit monitoring can detect subtle faults that only appear under certain conditions.
A failing ignition coil can damage the catalytic converter over time if misfires are persistent, so address the fault promptly even if the vehicle seems to run fine.

Can I keep driving with P2320?

It is generally safe to drive short distances to a repair shop, but avoid heavy acceleration or sustained high-speed driving to prevent catalytic converter damage from unburned fuel. If the check engine light is flashing, stop driving and have the vehicle towed, as a severe misfire can quickly ruin the catalytic converter.

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.