P0352 is an ignition system trouble code that can leave you wondering if your engine is about to fail. The good news is that this code is usually straightforward to track down once you understand what it points to. In most cases, P0352 means the engine computer has detected a problem with the ignition coil circuit for cylinder 2. That can be a bad coil, wiring fault, or even an intermittent ECU issue. In this guide, you’ll learn what P0352 means, common symptoms, how to diagnose it, and what it typically costs to repair.
What Does P0352 Mean?
P0352 is an OBD-II diagnostic trouble code that stands for “Ignition Coil ‘B’ Primary/Secondary Circuit Malfunction.” In plain language, your ECU has detected an electrical problem in the ignition coil circuit for cylinder 2 (often labeled coil “B” on many systems).
The ECU constantly monitors coil control and feedback signals. If it sees voltage that’s too high, too low, or erratic on the cylinder 2 coil circuit, it sets P0352 and usually turns on the check engine light. This can cause misfires, rough running, and poor fuel economy if not corrected.
Quick Reference
- Code: P0352
- Definition: Ignition Coil “B” / Cylinder 2 Primary/Secondary Circuit Malfunction
- Severity: Moderate to high (can damage catalytic converter if ignored)
- Most common cause: Failed ignition coil on cylinder 2
- Typical fix: Replace coil, repair wiring, clear codes, verify no misfire
Real-World Example / Field Notes
In the shop, I see P0352 most often on vehicles with individual coil-on-plug systems. A common scenario: the customer complains of a rough idle and flashing check engine light under load. Scan tool shows P0352 and a misfire on cylinder 2. Swapping the coil from cylinder 2 to another cylinder moves the misfire and the code, confirming a bad coil. Occasionally, though, the coil tests good and the real culprit is a broken wire in the harness where it bends near the valve cover. Visual inspection and a simple wiggle test while watching live data usually reveal the issue.
Symptoms of P0352
- Check engine light on: P0352 will usually store as a current or pending code, often with a steady or flashing MIL.
- Engine misfire: You may feel a stumble, especially at idle or under acceleration, as cylinder 2 fails to fire consistently.
- Rough idle: The engine may shake at stoplights and feel uneven due to the missing cylinder.
- Loss of power: Acceleration can feel weak or jerky because you’re effectively running on fewer cylinders at times.
- Poor fuel economy: Unburned fuel and inefficient combustion reduce MPG and can cause a fuel smell from the exhaust.
- Hard starting: In some cases, especially when cold, the engine may crank longer or start roughly.
- Exhaust odor or popping: Raw fuel entering the exhaust can cause a strong smell, occasional pops, or backfire.
Common Causes of P0352
Most Common Causes
- Failed ignition coil on cylinder 2 (internal short or open winding).
- Worn or fouled spark plug on cylinder 2 causing abnormal coil load.
- Damaged ignition coil connector (loose pins, corrosion, broken lock tab).
- Open or shorted wiring between ECU and cylinder 2 coil (control or power feed).
Less Common Causes
- ECU (PCM) driver failure for the cylinder 2 coil circuit.
- Moisture intrusion in the coil well (oil or coolant leaks into plug tube).
- Aftermarket remote start or alarm wiring spliced into ignition circuits.
- Incorrect or low-quality replacement coils or spark plugs.
- Ground issues affecting ignition system voltage stability.
Diagnosis: Step-by-Step Guide
Before you dive in, you’ll want a basic tool set: a quality OBD-II scan tool (preferably with live data and Mode $06), a digital multimeter, basic hand tools, and if possible, a spark tester. A wiring diagram for your specific vehicle helps a lot when checking power, ground, and coil control circuits.
- Confirm the code and check for companions. Scan for codes and note any related DTCs such as misfire codes (P0302) or other coil circuit codes. Clear codes and see which ones return first.
- Inspect ignition coil and connector on cylinder 2. With the engine off, remove the coil on cylinder 2. Look for cracks, burn marks, melted plastic, oil in the plug well, or corrosion on terminals. Check that the connector locks firmly.
- Swap coils to isolate the fault. Move the cylinder 2 coil to another cylinder and put a known-good coil on cylinder 2. Clear codes and test-drive. If the code or misfire follows the coil, the coil is bad. If it stays on cylinder 2, suspect wiring or ECU.
- Check the spark plug on cylinder 2. Remove and inspect the plug. Look for heavy deposits, cracks, worn electrodes, or incorrect gap. Replace if worn or questionable, and make sure it’s the correct type and heat range.
- Verify power and ground at the coil connector. With the key on (engine off), use a multimeter to check for battery voltage at the coil power feed. Check for a solid ground if your design uses a dedicated ground wire. Compare readings to another known-good coil.
- Test the coil control signal. With a test light or scope (ideal), check the coil control wire from the ECU while cranking or running. You should see a pulsed signal. No signal can indicate a broken wire or ECU driver issue.
- Perform a wiggle test on the harness. While monitoring live data or watching for misfire counts, gently move the wiring harness near the coil and along the route to the ECU. If the engine stumbles or the signal drops out, you likely have an intermittent wiring fault.
- Check Mode $06 data (if available). Some scan tools allow you to view misfire counters per cylinder. High counts on cylinder 2, even without a constant misfire, can confirm an ignition issue tied to that cylinder.
- Inspect ECU and grounds (if all else checks out). If the coil, plug, wiring, and connectors are all confirmed good and you still have P0352, you may be dealing with a failing ECU coil driver or a major ground issue. At this point, professional testing or ECU replacement may be needed.
Pro Tip: Always clear codes and perform a proper road test after each repair step. Many people replace coils or plugs and never confirm that the ECU sees clean ignition signals under load, which can leave intermittent problems unsolved.
Possible Fixes & Repair Costs
Most P0352 repairs are straightforward once you pinpoint the cause. The most common fix is replacing the ignition coil on cylinder 2, often along with the spark plug if it’s old or worn. Wiring repairs may involve splicing in new sections of wire or replacing a damaged connector. In rare cases, the ECU has to be repaired or replaced and programmed.
Typical repair costs vary by vehicle and shop rates. As a rough guide: a single ignition coil replacement usually runs $120–$300 parts and labor, a set of spark plugs $150–$400, wiring or connector repairs $150–$350, and an ECU replacement can range from $600 to over $1,500. Costs depend on parts quality (OEM vs aftermarket), engine layout (easy vs hard access), and local labor rates.
Can I Still Drive With P0352?
You can often drive short distances with P0352, but it’s not recommended for long-term use. A misfiring cylinder sends unburned fuel into the exhaust, which can quickly overheat and damage the catalytic converter. You’ll also experience reduced power, rough running, and potentially unsafe driving behavior in traffic or on the highway. If the check engine light is flashing, that’s the ECU warning you about active misfire; in that case, reduce load immediately and get the vehicle checked as soon as possible.
What Happens If You Ignore P0352?
Ignoring P0352 can turn a relatively simple coil or plug replacement into a much more expensive repair. Continuous misfires can destroy the catalytic converter, foul the oxygen sensors, and contaminate the engine oil with fuel. Over time, severe misfires may also stress engine mounts and internal components. Fixing the root cause early is far cheaper than replacing exhaust and emissions parts later.
Related Codes
- P0399 – Ignition Coil “R” Primary/Secondary Circuit
- P0364 – Reserved
- P0363 – Misfire Detected Fueling Disabled
- P0362 – Ignition Coil “L” Primary/Secondary Circuit
- P0361 – Ignition Coil “K” Primary/Secondary Circuit
- P0360 – Ignition Coil “J” Primary/Secondary Circuit
- P0359 – Ignition Coil “I” Primary/Secondary Circuit
- P0358 – Ignition Coil “H” Primary/Secondary Circuit
- P0357 – Ignition Coil “G” Primary/Secondary Circuit
- P0356 – Ignition Coil “F” Primary/Secondary Circuit
Key Takeaways
- P0352 means the ECU detected an electrical problem in the ignition coil circuit for cylinder 2.
- Common symptoms include a check engine light, misfire, rough idle, and loss of power.
- The most frequent cause is a failing coil, but wiring, connectors, and spark plugs should also be checked.
- Diagnosis usually involves visual inspection, coil swapping, voltage checks, and scan tool data.
- Driving with P0352 can damage the catalytic converter if you ignore it for too long.
- Most repairs are affordable if handled early, before misfires cause secondary damage.
Vehicles Commonly Affected by P0352
P0352 shows up on many modern vehicles that use coil-on-plug ignition systems. It’s especially common on domestic brands like Ford, GM (Chevrolet, GMC, Buick), and Chrysler/Dodge/Jeep, where individual coils sit directly on each spark plug. Import brands such as Toyota, Lexus, Honda, Acura, Nissan, Infiniti, Hyundai, and Kia also see this code regularly. You’ll find it on everything from compact cars and family sedans to SUVs, pickups, and vans. High-mileage engines and vehicles with overdue tune-ups are most likely to trigger this code.
FAQ
Can I clear P0352 and keep driving if the car feels fine?
You can clear the code, but if the underlying problem still exists, P0352 will usually return. Even if the engine feels okay now, an intermittent coil or wiring issue can worsen quickly and leave you with a hard misfire. It’s better to diagnose and fix the cause rather than repeatedly clearing the code.
Is P0352 always caused by a bad ignition coil?
No. A bad coil is the most common cause, but not the only one. Damaged wiring, poor connections, fouled spark plugs, and even ECU driver faults can all trigger P0352. That’s why swapping coils and checking voltage and wiring are important steps before throwing parts at the problem.
How do I know which cylinder is cylinder 2 on my engine?
Cylinder numbering depends on the engine layout and manufacturer. On many inline engines, cylinder 1 is at the front (belt side) and the rest follow in order. On V6 and V8 engines, each bank is numbered differently. Your owner’s manual, service manual, or a reliable online diagram for your specific engine will show exactly which one is cylinder 2.
Can a bad spark plug cause P0352 even if the coil is good?
Yes. A severely worn or fouled spark plug can cause abnormal resistance and stress the coil, leading the ECU to detect a circuit fault. In practice, many shops replace both the coil and plug on the affected cylinder, especially if the plugs are due for service anyway.
How quickly should I fix a P0352 code?
You should address P0352 as soon as you reasonably can. It’s not usually an immediate “tow it now” emergency unless the engine is running very poorly, but continued driving with a misfire can damage expensive components. Scheduling diagnosis and repair within a few days is a smart move.