Ignition Coil A Primary/Secondary Circuit Malfunction
The ECU detected a problem with ignition coil A's electrical circuit—either the primary (low-voltage) or secondary (high-voltage) side isn't working correctly. Think of it like a transformer that's broken; it's not converting electrical power properly to create the spark.
The ECU monitors the primary coil circuit by measuring current draw and dwell time (how long the coil charges). It also detects secondary circuit voltage and spark delivery. If current is too high, too low, or absent—or if spark plug firing is detected as weak—a fault is triggered.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Primary coil current draw | 3–8 amps during charging | Out of range or no current detected |
| Secondary spark voltage delivery | 20–40 kV to fire plug | Below 15 kV or erratic |
Code P0352 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, P0352 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.