P0352 code: Ignition Coil B Primary/Secondary Circuit
P0352 means ignition Coil B Primary/Secondary Circuit. The code says where to look, not what failed — the fix depends on which cause your car actually has.
What P0352 means
P0352 reports an electrical fault in the circuit of ignition Coil B — the cylinder 2 coil on coil-on-plug engines. Each coil has a primary circuit (the low-voltage side the ECM switches to trigger the spark) and a secondary circuit (the high-voltage side that fires the plug); the ECM monitors the primary and sets this code when it sees an open or short instead of the expected electrical response. That makes P0352 fundamentally a wiring-and-coil problem rather than a worn spark plug, which fails by sparking weakly rather than by breaking the circuit. Typical causes, roughly in order of likelihood: a failed coil, a loose or corroded connector at the coil, chafed harness wiring, a blown fuse in the coil power feed, and rarely a bad driver in the ECM. Since cylinder 2 stops sparking, expect the companion misfire code P0302 alongside it.
P0352 symptoms
- Rough idle and shaking from a cylinder 2 misfire
- Hesitation or stumble under acceleration
- Flashing check-engine light while the misfire is active
- Raw-fuel smell from the exhaust
- Reduced power and fuel economy
- Companion misfire code P0302 is common
What it costs to fix P0352
Typical range: $60–$400 · about ~0.2–2 hrs of labor
| If the cause is… | Part | Labor |
|---|---|---|
| Ignition coil (single) | $30–$150 | ~0.2–0.5 hrs |
| Wiring or connector repair | $5–$50 | ~0.5–2 hrs |
| Spark plugs (while in there) | $20–$100 | ~0.5–1.5 hrs |
On most four-cylinder engines the coils sit right on top and a coil swap is a 15-minute job, keeping labor at the low end. Cylinder numbering varies by manufacturer, and on some V6/V8 layouts cylinder 2 can sit on the harder-to-reach bank — rear-bank coils on a transverse V6 can require intake removal and 1–3 hours of labor.
The price swings on which cause it turns out to be — so confirm the cause before paying. Diagnose P0352 for my exact vehicle →
How to fix P0352
Easy — basic tools, most owners can do this
- Inspect the connector on cylinder 2's coil
Pop the connector off coil B (cylinder 2), look inside for corrosion, oil, or spread pins, and make sure the locking tab still clicks. Cleaning the terminals and reseating the plug fixes a surprising number of these codes for free.
- Trade coil 2 with another cylinder's coil
Install coil 2 on a different cylinder, clear the code, and drive it. A P0352 that turns into a different coil-circuit code proves the coil failed; a P0352 that stays put shifts suspicion to the wiring.
- Verify voltage at the connector
Key on, back-probe the feed terminal at the coil 2 connector for battery voltage. Missing voltage sends you upstream to the fuse and harness; present voltage means the coil or its control (trigger) wire back to the computer is the issue.
- Examine the wiring run to coil 2
Check coil B's section of the harness for rub-through, heat damage near the exhaust side, or rodent chew. Repair breaks properly with solder and heat-shrink so vibration doesn't reopen the fault.
DIY or shop? The connector check and coil swap are entry-level DIY and cover the most likely causes. Voltage testing needs only a cheap multimeter. Reserve the shop for a fault you can't find in the visible wiring — an intermittent open deep in the harness or a rare ECM coil-driver failure needs a wiring diagram and a scope.
Tools for the DIY steps: OBD-II scanner · Multimeter · Socket set for coil bolts · Contact cleaner · Solder and heat-shrink tubing (for wire repair)
Not sure which step applies to your car? Get the likely cause for your exact vehicle before buying anything for P0352.
Start a case with P0352 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 P0352?
Redline can’t determine from a symptom or code alone whether your car is safe to drive.
P0352: common questions
Should I replace all the coils or just coil 2?
If one coil failed from age and the others share its mileage, some owners replace all of them to avoid repeat visits — that's a judgment call, not a requirement. Replacing just the confirmed-bad coil is perfectly valid, especially after a swap test proves it. Wiring or connector faults, of course, don't call for new coils at all.
What does "primary/secondary circuit" actually mean?
Each coil has two windings: the primary is the low-voltage side the engine computer switches on and off, and the secondary is the high-voltage side that actually fires the spark plug. P0352 means the computer detected an open or short in that circuit for coil B — an electrical break, not just a weak spark.
Can I keep driving with P0352?
Treat it with some urgency — Redline can't make the driving call from the code alone. Even with a steady light and a mild stumble, cylinder 2 is feeding raw fuel to the catalytic converter, so get it repaired promptly; a flashing light means an active misfire is overheating the converter — stop driving and get it checked.
Will P0352 fail an emissions inspection?
Almost certainly — in areas with OBD-based testing, any active check-engine light is typically an automatic fail, and a misfiring cylinder raises tailpipe emissions on top of that. Fix the fault and let the monitors reset before testing.
Symptoms that trigger P0352
Drivers who get this code often notice one of these. Each has its own causes and cost guide:
Related trouble codes
Don’t have a scanner yet? A ~$25 Bluetooth adapter reads codes like P0352 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 P0352 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.