What Does P0362 Mean?
The ECM has detected a primary or secondary circuit malfunction in ignition coil L, serving cylinder #12 on twelve-cylinder engines such as V12 or W12 configurations. This is the final coil in the ignition system and its driver circuit monitoring has identified abnormal operation. As with other coil codes, the affected cylinder will misfire, though on a 12-cylinder engine the effect is somewhat diluted by the remaining cylinders.
Common Causes
40%
Failed ignition coil L from internal winding deterioration due to high heat environment in V12/W12 engine compartments
25%
Damaged wiring or connector in the coil L circuit, particularly where harnesses are routed in confined, high-temperature areas
20%
Spark plug on cylinder 12 worn beyond specification or with cracked insulator
15%
ECM or bank-specific ignition control module driver failure for cylinder 12
Diagnostic Steps
1
Swap coil L with a known-good coil from another cylinder, clear codes, and monitor for fault recurrence to determine if the coil or the circuit is at fault.
2
Measure coil L primary and secondary winding resistances per manufacturer specification. On 12-cylinder engines, have readings from all coils for comparison.
3
Inspect coil L connector terminals for heat discoloration, corrosion, or push-back. Verify connector lock engagement is positive.
4
Remove and inspect the cylinder 12 spark plug for fouling, wear, or damage. Twelve-cylinder engines often have difficult plug access, leading to deferred maintenance.
5
Verify ECM trigger signal and power supply at the coil L connector during cranking using a labscope.
Estimated Repair Cost
$100 - $500
Parts + labor, varies by vehicle and location
The ECM has detected a primary or secondary circuit malfunction in ignition coil L, serving cylinder #12 on twelve-cylinder engines such as V12 or W12 configurations. This is the final coil in the ignition system and its driver circuit monitoring has identified abnormal operation. As with other coil...
The most common cause of P0362 (Ignition Coil L Primary/Secondary Circuit Malfunction) is: Failed ignition coil L from internal winding deterioration due to high heat environment in V12/W12 engine compartments
Typical repair costs for P0362 range from $100 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
A misfire on cylinder 12 of a V12/W12 produces minor but measurable power loss. Unburned fuel in the exhaust can overheat the downstream catalytic converter if the condition persists.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0362 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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