P0352 - Ignition Coil B Primary/Secondary Circuit Malfunction
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System
Powertrain (Engine & Gearbox)
Related Fault Codes
Technical Description
P0352 is triggered when the PCM (Powertrain Control Module) detects an issue with the ignition coil 'B' (typically cylinder 2) primary or secondary circuit. Each coil is controlled by a driver in the PCM that grounds the circuit to charge the coil. If the PCM does not detect the inductive kick (flyback voltage) when the circuit is opened, it identifies a malfunction. This is a circuit-specific fault, meaning the PCM has monitored an electrical deviation in the wiring, the coil itself, or the internal PCM driver. The PCM may disable fuel injection for that cylinder to prevent catalyst damage.
Possible Causes
Faulty ignition coil (internal open or short circuit)
Wiring issues (chafed insulation, corrosion in the connector for cylinder 2)
Poor ground connection for the ignition system
Internal PCM/ECU driver failure
Symptoms
Recommended Solution
- Visual Inspection: Check the connector at ignition coil 2 for oxidation or loose pins. Inspect wiring looms for chafing or heat damage.
- Swap Test: Swap the ignition coil from cylinder 2 with cylinder 1. Clear codes and check if the code changes to P0351. If the fault follows the coil, replace it.
- Multimeter test: Check for 12V supply at the coil connector and verify ground continuity (should be < 0.5 Ohms).
- Oscilloscope: Check the trigger signal waveform from the PCM to ensure the driver is pulsing. If no signal is present and wiring is intact, the PCM may be faulty.
- Component replacement: Replace the faulty ignition coil and consider replacing spark plugs simultaneously.
Mechanic's Tip
Before replacing expensive components, always double-check wiring and connections. 80% of all sensor faults are actually due to corroded contacts or broken wires.
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