# P0352: Ignition Coil "B" Primary/Secondary Circuit **Verdict:** Drive to a shop this week Ignition and misfire - Generic OBD-II code, applies to all gasoline cars and light trucks sold in the US since 1996. - **Typical cost:** $100-$700 - **Urgency:** This week - **Most likely:** Failed ignition coil for cylinder 2 - **DIY?:** Often yes, if coils are on top ## Quick answer P0352 means the engine computer has found a problem in the circuit for ignition coil "B", which on most engines is the coil for cylinder 2. It is not seeing the electrical response it expects when it fires that coil. A failed coil is the most common cause, and the code often comes with a cylinder 2 misfire. ## What does P0352 mean? Each ignition coil steps 12-volt power up to the very high voltage that jumps a spark plug gap. The engine computer, or an igniter module on some engines, switches current through the coil's primary winding. When it cuts that current, the collapsing magnetic field fires the plug through the secondary winding. Most modern engines have one coil sitting on top of each spark plug. P0352 is the circuit code for coil "B". On most coil-on-plug engines coil B fires cylinder 2, but some makers letter coils by firing order, and on waste-spark coil packs "B" can serve a pair of cylinders. The computer watches primary current or a feedback signal from the coil and sets P0352 when it sees an open, a short or no response. On many vehicles it sets on the first trip, and the computer may shut off fuel to that cylinder to protect the catalytic converter. ## What are the symptoms of P0352? - Rough idle or shaking, especially at stoplights - Loss of power or hesitation when accelerating - Check engine light on, or flashing during heavy misfire - Misfire code P0302 stored at the same time - Lower fuel economy or a raw-fuel smell from the exhaust ## What causes P0352? Ranked from most to least likely. Check them in this order: the cheap, common causes first. 1. **Failed ignition coil B** (most common). Coils sit on top of the engine and endure constant heat and vibration, so their windings or built-in driver electronics eventually fail. Failure is more common at higher mileage and on engines run long past their spark plug interval. Swapping coil B with a neighboring coil and seeing whether the misfire moves is a quick, reliable test. 2. **Damaged coil connector or wiring** (common). The coil connector and its short pigtail live in the heat on top of the engine. Brittle plastic locks break, pins corrode, and wires crack where they flex. Oil leaking from a valve cover gasket or spark plug tube seal can also soak the connector. A loose plug can come and go with engine movement and vibration. 3. **Worn spark plug or damaged coil boot** (less common). A spark plug with a badly worn gap needs higher voltage to fire, which strains the coil, and a cracked or oil-soaked boot can let spark leak to ground. On some engines that stress shows up as a coil circuit code. Look at the plug and boot whenever coil B is removed, and replace worn plugs. 4. **Coil power, ground or computer driver fault** (rare). Coils share a power feed and a ground, and the engine computer has a separate driver for each one. A blown fuse or bad ground usually sets several coil codes at once. A shorted coil can damage its driver inside the computer, so a shop checks resistance and the circuit before replacing either part. ## How do you diagnose P0352? 1. Read all codes, especially P0302 or other coil codes that suggest a shared power or ground fault. 2. Confirm which cylinder coil B fires on your engine using service information. 3. Inspect coil B's connector, wiring and boot for damage, oil or corrosion. 4. Swap coil B with another coil and see whether the misfire or circuit code moves with it. 5. Check coil power, ground and the control signal from the computer with a meter or scope. ## How do you fix P0352, and what does it cost? | Fix | Typical cost | What it involves | | --- | --- | --- | | Replace ignition coil B | $150-$400 | Includes the coil and labor; coils under an intake plenum cost more to reach. | | Repair coil connector or wiring | $100-$300 | Replaces a cracked connector or repairs damaged wires. | | Replace spark plugs with the coil | $150-$700 | Recommended if plugs are due; V6 engines with rear-bank plugs sit at the top of the range. | Full price breakdowns: [ignition coil replacement cost](/cost/ignition-coil-replacement), [spark plug replacement cost](/cost/spark-plug-replacement). ## Is it safe to drive with P0352? > **Drive to a shop this week.** You can usually drive gently to a shop if the engine runs smoothly. If the check engine light flashes or the engine shakes hard, stop driving, since unburned fuel can overheat and damage the catalytic converter. ## Will P0352 fail an emissions test? With P0352 stored and the check engine light on, the car fails an OBD-based emissions test in most states. A coil fault usually causes misfires, which can raise hydrocarbon emissions and stop the misfire and catalyst monitors from passing. After the repair, clear the code and drive until all readiness monitors complete before testing. ## After the repair: clearing P0352 Clear the code, then let the engine idle and drive at mixed speeds once it is fully warm. On a scan tool, the misfire counter for the cylinder coil B fires should stay at or near zero. If the engine runs smoothly and neither P0352 nor a misfire code returns after several days, the repair worked. ## How to prevent P0352 - Replace spark plugs at the interval in your owner's manual to reduce strain on the coils. - Fix valve cover and spark plug tube seal leaks before oil soaks coils and boots. - Make sure each coil connector clicks into its lock after any work on top of the engine. - Use dielectric grease on coil boots when plugs are changed, if the maker recommends it. ## Codes often seen with P0352 - [P0351](/codes/p0351): Ignition Coil "A" Primary/Secondary Circuit - [P0302](/codes/p0302): Cylinder 2 Misfire Detected - [P0300](/codes/p0300): Random/Multiple Cylinder Misfire Detected - [P0420](/codes/p0420): Catalyst System Efficiency Below Threshold (Bank 1) ## Frequently asked questions ### Can I drive with a P0352 code? You can usually drive a short distance gently if the engine runs smoothly. If it shakes, loses power or the check engine light flashes, stop driving, because misfires send unburned fuel into the catalytic converter. Many cars shut off fuel to the affected cylinder, which also reduces power. ### Which cylinder is ignition coil B? On most coil-on-plug engines, coil B fires cylinder 2. Some makers letter coils in firing order or use waste-spark packs where coil B serves two cylinders. Check service information for your engine, or look for a misfire code such as P0302 stored alongside P0352 as a clue. ### How much does it cost to fix P0352? Most P0352 repairs cost $100 to $700 at an independent shop. A new coil runs about $150 to $400 and a connector or wiring repair $100 to $300. Replacing spark plugs at the same visit costs $150 to $700, with rear-bank V6 plugs at the top of the range. ### Can I replace an ignition coil myself? Often yes, if the coils sit on top of the engine and are held by one bolt each. Unplug the coil, pull it straight out, install the new one and plug it in. Coils under an intake plenum on some V6 engines take more work and may be better left to a shop. ### Should I replace all the ignition coils at once? Usually it is not necessary to replace all coils when one fails. Replacing only the faulty coil is the common choice. Some owners replace all of them on high-mileage engines where coils are hard to reach, to avoid repeat labor, but that is a judgment call, not a requirement. ### What is the difference between P0351 and P0352? Both are ignition coil circuit codes, but P0351 is for coil A, usually cylinder 1, and P0352 is for coil B, usually cylinder 2. Each points to its own coil and wiring. If several coil codes appear together, check the shared power feed, fuse and ground first. ### Can a bad spark plug cause P0352? It can contribute. A worn plug with a wide gap demands more voltage, which strains the coil and can trigger a circuit code on some engines. A cracked or oily boot can also leak spark. Inspect the cylinder 2 plug and boot whenever you remove coil B. ### Will a bad coil damage the catalytic converter? It can if you keep driving with a misfire. Unburned fuel from the dead cylinder reaches the converter, where it burns and overheats the catalyst. A flashing check engine light means this is happening. Fixing the coil promptly protects a converter that costs far more than a coil. ### Why did P0352 come back after a new coil? The cause was probably the connector, wiring or another part of the circuit rather than the coil. A low-quality replacement coil can also fail quickly. A shop should check power, ground and the control signal at the connector, and inspect the plug and boot, before replacing more parts. ### Will P0352 pass inspection? No, P0352 with the check engine light on fails an OBD-based emissions test in most states. Misfires from a bad coil can also stop the misfire and catalyst monitors from completing. Repair the circuit, clear the code and drive normally for several days before testing. ## Sources - [SAE J2012: Diagnostic Trouble Code Definitions](https://www.sae.org/standards/content/j2012_201812/) - [EPA: On-Board Diagnostics (OBD)](https://www.epa.gov/state-and-local-transportation/vehicle-emissions-board-diagnostics-obd) ## Other ignition and misfire codes - [P0332 Knock Sensor 2 Circuit Low (Bank 2)](https://diagxcar.com/codes/p0332) - [P0335 Crankshaft Position Sensor "A" Circuit](https://diagxcar.com/codes/p0335) - [P0336 Crankshaft Position Sensor "A" Circuit Range/Performance](https://diagxcar.com/codes/p0336) - [P0339 Crankshaft Position Sensor "A" Circuit Intermittent](https://diagxcar.com/codes/p0339) - [P0340 Camshaft Position Sensor "A" Circuit (Bank 1 or Single Sensor)](https://diagxcar.com/codes/p0340) - [P0341 Camshaft Position Sensor "A" Circuit Range/Performance (Bank 1 or Single Sensor)](https://diagxcar.com/codes/p0341) - [P0344 Camshaft Position Sensor "A" Circuit Intermittent (Bank 1 or Single Sensor)](https://diagxcar.com/codes/p0344) - [P0345 Camshaft Position Sensor "A" Circuit (Bank 2)](https://diagxcar.com/codes/p0345) - [P0351 Ignition Coil "A" Primary/Secondary Circuit](https://diagxcar.com/codes/p0351) - [P0365 Camshaft Position Sensor "B" Circuit (Bank 1)](https://diagxcar.com/codes/p0365) ## Symptoms - [Why is my car idling rough?](https://diagxcar.com/symptoms/rough-idle) - [Why does my car shake at idle?](https://diagxcar.com/symptoms/car-shakes-at-idle) - [Why does my car hesitate when I accelerate?](https://diagxcar.com/symptoms/car-hesitates-when-accelerating) - [Why does my car lose power when accelerating?](https://diagxcar.com/symptoms/car-loses-power-when-accelerating) ## Repair costs - [Ignition coil replacement cost](https://diagxcar.com/cost/ignition-coil-replacement): $150-$400 - [Spark plug replacement cost](https://diagxcar.com/cost/spark-plug-replacement): $120-$450 --- Source page: https://diagxcar.com/codes/p0352 Updated: 2026-11-03 General information, not a substitute for a qualified mechanic.