What Does P0364 Mean?
The ECM has detected an intermittent fault in the ignition coil L primary or secondary circuit. Unlike P0362 which indicates a hard failure, this code signals that coil L's circuit behavior is erratic, with the signal dropping in and out. The misfire on cylinder 12 may come and go with engine temperature, vibration, or load changes, making it harder to reproduce and diagnose.
Common Causes
35%
Ignition coil L with an intermittent internal winding fault that fails under thermal stress but tests normal when cold
30%
Loose or intermittent connection at the coil L connector from worn terminal tension or thermal expansion/contraction cycling
20%
Intermittent break in the coil L wiring harness with a conductor fractured inside intact insulation
15%
ECM coil driver intermittent fault for the cylinder 12 output, often temperature-related
Diagnostic Steps
1
Monitor misfire counters on all cylinders using live data while driving under various conditions (idle, load, cold, hot). Cylinder 12 should show elevated misfire counts compared to other cylinders.
2
Perform a wiggle test on the coil L connector and wiring while monitoring for misfires on a labscope or through live misfire data.
3
Apply heat to the coil L using a heat gun (200°F) while monitoring for increased misfire rate. Many intermittent coil failures are temperature-dependent.
4
Inspect coil L boot for cracks, tears, or carbon tracking that could cause intermittent arcing under high-load, high-temperature conditions.
5
If coil and wiring test good, swap the coil to a different cylinder position and monitor for the intermittent fault to follow the coil.
Estimated Repair Cost
$80 - $450
Parts + labor, varies by vehicle and location
The ECM has detected an intermittent fault in the ignition coil L primary or secondary circuit. Unlike P0362 which indicates a hard failure, this code signals that coil L's circuit behavior is erratic, with the signal dropping in and out. The misfire on cylinder 12 may come and go with engine temper...
The most common cause of P0364 (Ignition Coil L Primary/Secondary Circuit) is: Ignition coil L with an intermittent internal winding fault that fails under thermal stress but tests normal when cold
Typical repair costs for P0364 range from $80 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Intermittent misfires cause unpredictable power fluctuations and can momentarily disable fuel to the affected cylinder for catalyst protection. This creates inconsistent engine behavior that may be unsafe during aggressive driving maneuvers.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0364 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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