P2320 indicates the powertrain control module (PCM) has detected an abnormal voltage condition in the secondary (high-voltage) circuit of ignition coil G. The secondary circuit is the path that delivers the high-voltage pulse from the coil to the spark plug, so a fault here typically means the coil is not producing or delivering a usable spark on that cylinder. Because ignition is cylinder-specific, this code is almost always accompanied by an engine misfire on the affected cylinder.
The coil itself is the single most common cause. Internal shorts, open windings, or cracked insulation in the secondary side prevent proper high-voltage output even though the primary circuit may appear normal.
Excessive gap, carbon fouling, oil deposits, or a cracked insulator raise the resistance the secondary circuit must overcome, which the PCM interprets as a secondary circuit malfunction.
A torn, oil-soaked, or carbon-tracked boot (or a worn plug wire on systems that still use them) leaks high voltage to ground and prevents the full secondary pulse from reaching the plug.
Moisture intrusion, corrosion on the coil harness terminals, or an incomplete latch at the connector can produce intermittent or low signals on the primary side, causing the secondary to misfire.
Chafed, heat-damaged, or pinned wiring between the PCM and the coil driver, or a short to ground in that circuit, will disrupt the trigger signal and the secondary spark.
Rare. The internal coil driver in the powertrain control module can fail, but this is only confirmed after every coil, plug, boot, and wiring issue has been ruled out.
Short trips at light load are usually possible, but a flashing Check Engine Light means an active misfire is dumping unburned fuel into the exhaust and can overheat and damage the catalytic converter. Limit driving and address it promptly if the light is flashing.
Often yes, because a failed coil is the most common cause, but it is worth inspecting the spark plug, boot, and connector at the same time so a worn plug or oil-fouled boot does not damage the new coil.
No. Online advice sometimes blames the computer, but P2320 is almost always caused by the coil, spark plug, boot, or wiring on that specific cylinder. The PCM should only be considered after every other possibility has been tested and eliminated, which is uncommon.
It can go inactive if the fault becomes intermittent, but the code will usually return until the underlying component is repaired. Clearing it without fixing the cause typically results in the code reappearing within the same drive cycle or the next one.