What Does P1365 Mean?
The secondary (high voltage) circuit of ignition coil A has failed or is operating outside normal parameters. This affects spark delivery to the cylinder(s) served by coil A.
Common Causes
50%
Failed ignition coil A with defective secondary winding
25%
Damaged spark plug wire or coil boot with high resistance
15%
Worn or fouled spark plug creating excessive load
10%
Carbon tracking on coil body or connector
Diagnostic Steps
1
Step 1: Inspect coil A exterior for cracks, oil contamination, or carbon tracking
2
Step 2: Measure coil A secondary resistance (typically 6,000-15,000 ohms)
3
Step 3: Check spark plug wires and boots for damage, burns, or high resistance
4
Step 4: Remove and inspect spark plug(s) for excessive gap, fouling, or damage
5
Step 5: Perform spark output test using calibrated spark tester under load
Estimated Repair Cost
$100 - $350
Parts + labor, varies by vehicle and location
The secondary (high voltage) circuit of ignition coil A has failed or is operating outside normal parameters. This affects spark delivery to the cylinder(s) served by coil A.
The most common cause of P1365 (Ignition Coil A Secondary Circuit Malfunction) is: Failed ignition coil A with defective secondary winding
Typical repair costs for P1365 range from $100 to $350, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Engine misfires will cause rough running and power loss. Unburned fuel can overheat and damage the catalytic converter if driven extensively.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1365 to identify the root cause.
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Quick Info
Category
Powertrain
System
Ignition System
Difficulty
Type
Manufacturer
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