Ignition Coil D Secondary Circuit Malfunction
The engine's computer detected a problem with the ignition coil D's secondary wiring circuit—the high-voltage side that fires the spark plug. Think of it like a broken wire in a lamp's power cord; the electricity can't flow properly to create the spark.
The ECM monitors the secondary circuit voltage and current feedback from ignition coil D during each firing event. It detects open circuits, shorts, or resistance outside normal ranges by measuring dwell time and coil saturation patterns. If voltage doesn't spike properly or current draw is abnormal, the fault is logged.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Secondary voltage spike | 15-25 kV during ignition event | Below 15 kV or no spike detected |
| Primary coil resistance | 0.4–2 ohms | Open circuit (infinite) or shorted (<0.2 ohms) |
Code P1368 is a moderate fault. You can generally drive to a workshop, but avoid long trips or high-load driving (motorway, uphill towing) until it is diagnosed. If the code keeps returning after clearing, or if you notice the symptoms listed above worsening, do not delay professional diagnosis. Many moderate codes have multiple possible root causes — a mechanic with live OBD data can identify the exact fault more efficiently than part-by-part trial and error.
Once the fault is repaired, P1368 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.