OBD-II trouble code
P0362: Ignition Coil 'L' Primary/Secondary Circuit
The twelfth and final letter the standard defines for ignition coils. Being at the end of the enumeration is a fact about the code numbering rather than about any engine, and it has consequences worth knowing before you start.
Quick facts
- System
- Powertrain
- Category
- Ignition
- Severity
- Medium severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $120 – $1,500
- DIY difficulty
- Shop recommended
What does P0362 mean?
This is where the generic ignition coil enumeration stops. The standard assigns letters A through L to individually driven ignition outputs and then simply ends — there is no M, no N, and no generic code number waiting for a thirteenth coil. A stored 'L' code therefore sits at a boundary that none of the eleven before it do, and understanding that boundary is more useful than any further variation on how a coil fails.
The first consequence applies to engines that exceed twelve outputs. Those engines exist — sixteen-cylinder configurations are rare but real, and so are engines with two plugs and two coils per cylinder, which reach the ceiling at six cylinders rather than twelve. When an engine has more ignition outputs than the standard has letters for, the manufacturer has to report the surplus somewhere else, and that somewhere else is its own enhanced code set rather than the generic list. If you are working on an engine like that, a generic reader and a generic lookup table will be actively misleading, and the manufacturer's own definitions are not a nice-to-have but the only correct reference.
The second consequence is more cheerful, and it applies when the code is genuine. Because 'L' is the twelfth letter and this engine has twelve outputs, the mapping between letters and outputs is exhaustive: twelve letters, twelve coils, one each, nothing left over and nothing shared. On engines that use only part of the alphabet, there is always a question about whether a given letter refers to one coil or to a pack driving a pair. Here that ambiguity cannot arise. It is worth building the full letter-to-cylinder map once from the manufacturer's diagram and keeping it, because every code in this family on this engine will resolve against the same twelve-entry table and you will never have to work it out again.
The third point is about money, and it is the one most likely to save some. Large-capacity multi-cylinder engines are frequently members of a shared architecture, built from the same bore spacing, the same heads and the same ancillaries as a smaller engine sold in far greater numbers. Where that is the case the ignition coil is often a common part, and the identical component can appear in the parts catalogue for the higher-volume engine at a substantially lower price and with real aftermarket availability. Compare the part numbers rather than accepting the first listing you are shown. Where the coil genuinely is unique to a low-volume engine, expect dealer pricing and order it only after the diagnosis is proven.
As always with a lettered coil code, the letter identifies an output in the manufacturer's own ordering, not a position you can count to by looking at the engine.
Common causes
- Failed ignition coil on the twelfth output of a twelve-cylinder engine
- Open or short in the coil primary drive wiring between the coil and its control module
- Corroded, spread or backed-out pin in the coil connector
- Cracked or hardened coil boot allowing the spark to track to the cylinder head
- Worn spark plug raising required firing voltage until the coil breaks down internally
- Failed driver output inside the control module serving that ignition output
- Damaged harness branch shared with other coils, which usually sets several letters at once
- Generic definition applied to a manufacturer-specific code on an engine with more than twelve ignition outputs
Symptoms
- Check engine light on, sometimes flashing if the misfire is severe
- Misfire on one cylinder that a twelve-cylinder engine hides remarkably well
- Slight roughness at idle, easier to see in live misfire counters than to feel
- Reduced power that is modest relative to the engine's total output
- Unburnt fuel smell from the exhaust
- Cylinder-specific misfire codes stored alongside this one
Diagnostic steps
- 1.Count the engine's ignition outputs. If there are more than twelve, the generic list cannot describe this fault and the manufacturer's own definitions are the only valid reference.
- 2.Read all stored codes together. A cylinder-specific misfire code names the physical cylinder outright, which the letter alone never does.
- 3.Build the complete letter-to-cylinder map from the manufacturer's diagram for this exact engine. With twelve letters and twelve outputs the mapping is exhaustive, so the table is worth writing down once and keeping.
- 4.Check whether the same coil is also fitted to a smaller, higher-volume engine in the same family before ordering parts. Where the part number is shared, the identical component is often available for considerably less.
- 5.Inspect the connector and pins before touching the coil. Backed-out and corroded pins are cheap to fix and are commonly found on engines that stand for long periods.
- 6.Remove the coil and examine the boot and the spark plug together. A tracked boot and a worn plug frequently explain a coil that has been driven to breakdown rather than one that simply failed.
- 7.Measure the coil's primary and secondary resistance where a specification is published, and compare against the eleven identical coils on the same engine as well as against the book figure.
- 8.If several letters have set at once, stop testing individual coils and look for the shared item — a supply, a ground, a relay or a harness branch feeding that group.
Repair cost
$120 – $1,500
Coils for large multi-cylinder engines run $120 to $500 each at dealer pricing, but the same part is often catalogued far more cheaply under a smaller engine in the same family, so checking part numbers is worth real money here. Access varies enormously: some coils lift out in minutes under a cover, others require intake or cover disassembly and three or four hours of labour. A single-coil repair commonly lands between $300 and $1,500 all in. A connector or boot repair can settle the fault for well under $200, which is the strongest argument for inspecting before ordering.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with ignition coil replacement preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
Leave this one to a qualified shop. It typically involves emissions-critical components, refrigerant handling, or other work that requires manufacturer-grade tooling, training, or certification. DIY attempts often produce a more expensive problem than the original code.