P0362 code: Ignition Coil L Primary/Secondary Circuit (Cylinder 12)
P0362 means ignition Coil L Primary/Secondary Circuit (Cylinder 12). The code says where to look, not what failed — the fix depends on which cause your car actually has.
What P0362 means
P0362 is the last code in the coil-circuit family: an open or short detected in the primary or secondary circuit of ignition Coil L, the coil for cylinder 12. Only twelve-cylinder engines have a coil L, so this code lives exclusively on V12s and their variants. The ECM individually drives all twelve coils, switching each primary winding to command the spark and monitoring the circuit for the correct electrical response; when coil L's circuit fails that check, this code sets, usually with companion misfire code P0312 for cylinder 12. The fault is electrical by definition — a worn spark plug degrades spark quality but cannot open the circuit — so diagnosis centers on the coil, its connector, and its wiring. Cylinder 12 sits at the end of a bank, where harness runs terminate and connectors see heat and vibration; chafe points and corroded terminals are worth a careful look before condemning the coil. A blown coil fuse or a failed ECM driver are the remaining, less common possibilities.
P0362 symptoms
- Misfire on cylinder 12 — easy to miss from the driver's seat on a V12
- Slight idle flutter or vibration under acceleration
- Check-engine light, flashing during active misfire
- Unburned-fuel smell from the exhaust
- Small power loss; companion code P0312 usually present
What it costs to fix P0362
Typical range: $70–$500 · about ~0.3–2.5 hrs of labor
| If the cause is… | Part | Labor |
|---|---|---|
| Ignition coil (single) | $30–$150 | ~0.3–1.5 hrs |
| Wiring or connector repair | $5–$50 | ~0.5–2 hrs |
| Spark plugs (while in there) | $20–$100 | ~0.5–1.5 hrs |
As with the other V12 coil codes, the coil is a modest part and the money goes to access: engine covers, tight packaging, and end-of-bank location all add time, and V12-capable shops bill accordingly. Combining the repair with plugs and a look at the rest of that coil bank makes the most of the teardown.
The price swings on which cause it turns out to be — so confirm the cause before paying. Diagnose P0362 for my exact vehicle →
How to fix P0362
Advanced — usually a shop job unless you’re well equipped
- Find cylinder 12 and prepare for the access
Coil L exists only on twelve-cylinder engines. Locate cylinder 12 on the diagram for your engine; if it's at the back of a bank, budget time for removing covers and possibly cowl or intake parts, and have a replacement connector pigtail on hand before you start.
- Unplug the coil L connector gently
Connectors at the end of a bank harness spend years in heat and often go brittle. Release the lock carefully and inspect for a cracked shell, loose terminals, or melted plastic; if it breaks, splice in a new pigtail with crimped, sealed connections instead of taping it.
- Measure the trigger and feed wires end to end
With the battery disconnected and the ECM connector unplugged per the service manual, check the cylinder 12 trigger wire for continuity to the module and for any short to ground or to neighboring wires. Low resistance end to end and no shorts clears the harness; anything else localizes the damage before a part is bought.
- Swap or replace coil L once the wiring passes
Trade coil 12 with a healthy coil, or install a quality replacement if a second coil is just as hard to reach. Afterwards, confirm that P0362 and P0312 stay clear and that cylinder 12's misfire counter stays at zero over several drives.
- Escalate to driver testing at a shop
If wiring and coil both prove good and coil L still faults, the module's output for cylinder 12 needs testing with a scope. On engines with a module per bank, only that bank's module is in question, and replacement typically requires programming to the vehicle.
DIY or shop? This lands in advanced territory mostly because of where coil L usually sits and how fragile old connectors become at the end of a V12 harness. Reading codes and checking misfire counts is easy; the coil swap is DIY only if you can reach it without removing intake parts. Continuity testing is doable with a meter and a diagram, but harness repair in a hot, cramped area and anything involving the module are better left to a shop that works on twelve-cylinder cars.
Tools for the DIY steps: OBD-II scanner · Digital multimeter · Replacement connector pigtail · Crimp tool and heat-shrink butt connectors · Wiring diagram for your engine · Trim and cover removal tools
Not sure which step applies to your car? Get the likely cause for your exact vehicle before buying anything for P0362.
Start a case with P0362 and your car. Redline weighs these causes against what your car shows, and names the check that would settle it before you buy parts.
Can I drive with P0362?
Redline can’t determine from a symptom or code alone whether your car is safe to drive.
P0362: common questions
Which vehicles can actually set P0362?
Only those with twelve-cylinder engines — coil L pairs with cylinder 12, which doesn't exist on anything smaller. Seeing P0362 reported on a four-, six-, or eight-cylinder car points to a scan error, not a real fault.
How do I know it's the coil and not the wiring or ECM?
Swap coil 12 with a neighboring cylinder's coil and clear the codes. Code follows the coil: replace the coil. Code stays on cylinder 12: inspect that cylinder's connector and harness leg for corrosion and chafe, and verify the coil fuse — only after all that checks out does the ECM driver become a suspect, and it's a rare one.
Is it safe to keep driving a V12 with P0362?
Redline can't make that call from the code alone. The misfire is steadily overheating one bank's catalytic converter — an especially costly part on these cars — so get the circuit repaired promptly. With a flashing check-engine light, stop driving it until the circuit is repaired.
What's a realistic repair cost for P0362?
If it's the coil, the part itself is inexpensive — the cost is dominated by labor to get under the engine covers and by the shop's hourly rate. Wiring repairs cost little in materials but more in diagnosis. Either way it's a small bill next to the catalytic converter damage that prolonged misfiring can cause.
Related trouble codes
Don’t have a scanner yet? A ~$25 Bluetooth adapter reads codes like P0362 from your phone. See our guide to the best OBD2 Bluetooth adapters. Run a repair shop? See Redline for shops.
Generic OBD-II reference. Manufacturer-specific behavior varies. Confirm with a scan tool and, for safety-related codes, a professional inspection. Cost ranges are reference ranges, not quotes.
Seeing P0362 on your car?
Every problem becomes a Case. Tell Redline what the car is doing: it shows what the evidence supports, what’s still missing, and what to check next, before you approve a repair.
“Inner pad ~1 mm. Outer pad 3 mm.”
Next: check the slide pins move freely before buying parts.