What Does P2326 Mean?
Ignition Coil 'I' Secondary Circuit indicates the ECM has detected a malfunction in the secondary (high-voltage) winding circuit of ignition coil I, which corresponds to cylinder 9 on most engines. This code is specific to engines with 10 or more cylinders (V10, V12). The secondary circuit generates the high-voltage spark (20,000-40,000 volts) needed to ignite the air-fuel mixture.
Common Causes
40%
Failed ignition coil I with internal secondary winding open or shorted
25%
Worn or fouled spark plug on cylinder 9 causing excessive secondary resistance
20%
Damaged or carbon-tracked coil boot or spark plug well insulator
15%
ECM ignition driver circuit fault or poor ground connection
Diagnostic Steps
1
Step 1: Monitor misfire counters via Mode $06 data for cylinder 9 to confirm active misfire correlation with this coil.
2
Step 2: Swap ignition coil I with an adjacent known-good coil and clear codes. If the fault follows the coil, replace it.
3
Step 3: Remove and inspect the spark plug on cylinder 9 for wear, fouling, or cracked insulator. Gap should be 0.028-0.032 inches depending on application.
4
Step 4: Inspect the coil boot for carbon tracking, tears, or moisture intrusion. Check the spark plug well for oil or coolant contamination.
5
Step 5: Using a secondary ignition oscilloscope (or COP probe), verify the secondary firing voltage is between 8-15 kV and the spark line is consistent.
Estimated Repair Cost
$80 - $350
Parts + labor, varies by vehicle and location
Ignition Coil 'I' Secondary Circuit indicates the ECM has detected a malfunction in the secondary (high-voltage) winding circuit of ignition coil I, which corresponds to cylinder 9 on most engines. This code is specific to engines with 10 or more cylinders (V10, V12). The secondary circuit generates...
The most common cause of P2326 (Ignition Coil "I" Secondary Circuit) is: Failed ignition coil I with internal secondary winding open or shorted
Typical repair costs for P2326 range from $80 to $350, depending on the vehicle, location, and whether you do it yourself or go to a shop.
The vehicle may misfire causing rough running and reduced power. Avoid heavy load or high-speed driving until repaired to prevent catalytic converter damage.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P2326 to identify the root cause.
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Quick Info
Category
Powertrain
System
Ignition System
Difficulty
Type
Generic (SAE)
Recommended Tools
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