P0362 - Ignition Coil L Primary/Secondary Circuit Malfunction
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System
Powertrain (Engine & Gearbox)
Related Fault Codes
Technical Description
P0362 is set when the Engine Control Unit (ECU) detects an electrical abnormality in the primary or secondary circuit of ignition coil 'L' (typically corresponding to cylinder 12). The ECU monitors the feedback signal (often via an Ion Sensing circuit or Ignition Confirmation signal - IGF) to ensure a high-voltage spark occurred. If the ECU commands a spark but fails to see the expected voltage drop or current flow within the specified duty cycle window, the diagnostic logic triggers P0362. This failure prevents proper combustion in the affected cylinder.
Possible Causes
Defective ignition coil (internal short or open winding)
Wiring issues (loose connections, corrosion, or chafed wires)
Faulty spark plug (excessive resistance affecting the secondary circuit)
Internal Engine Control Unit (ECU) driver failure
Symptoms
Recommended Solution
- Visual inspection: Check the connector at ignition coil L for corrosion or bent pins. Inspect the harness for heat damage or rodent damage.
- Testing: Measure supply voltage (12V) to the coil and check ground integrity. Verify primary winding resistance (typically 0.5 – 2.0 Ohms depending on OEM specs).
- Advanced Diagnosis (Swap test): Swap ignition coil L with another cylinder. If the fault code follows the coil (e.g., changes to P0351), the coil is definitely faulty.
- Component replacement: Replace the defective ignition coil and inspect the spark plug. Clear codes and perform a road test.
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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