Ignition Coil B Primary/Secondary Circuit
The Powertrain Control Module (PCM) detected a malfunction in the primary or secondary electrical circuit of ignition coil 'B', which typically corresponds to cylinder number 2. This code is set when the PCM does not receive the expected voltage pulse feedback from the ignition coil circuit during engine operation.
This code should be addressed immediately to prevent damage to the catalytic converter from unburned fuel. Driving with a severe misfire can also cause poor performance, stalling, and further engine damage.
Common symptoms
- Illuminated or flashing Check Engine Light
- Engine misfire or rough idle
- Lack of engine power during acceleration
- Noticeable hesitation or surging while driving
- Decreased fuel economy
Likely causes
- Defective ignition coil 'B' (cylinder 2)
- Damaged, loose, or corroded wiring connector at the ignition coil
- Faulty spark plug in cylinder 2 causing secondary circuit resistance
- Open or shorted ignition coil circuit wiring harness
- Faulty Powertrain Control Module (PCM) or ignition module (rare)
What to check before replacing parts
Visually inspect the ignition coil B connector and wiring harness.
Look for: Look for loose connections, broken wires, melted insulation, or corrosion that could interrupt the electrical circuit.
Swap ignition coil B with another cylinder's coil (e.g., cylinder 1) and clear the codes.
Look for: If the trouble code moves to the new cylinder (e.g., P0351), it confirms the ignition coil itself is defective.
Remove and inspect the spark plug for cylinder 2.
Look for: Look for worn electrodes, carbon tracking, cracked porcelain, or fouling that could cause excessive resistance in the secondary circuit.
Test the ignition coil connector for proper power and ground using a multimeter or test light.
Look for: Verify there is battery voltage at the power feed and a pulsing ground signal from the PCM while the engine is cranking or running.
Check continuity of the wiring between the PCM connector and the ignition coil connector.
Look for: Look for infinite resistance (indicating an open circuit) or continuity to ground (indicating a short) which points to a wiring harness failure.
This page explains the generic P0352 definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
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