P0358 - Ignition Coil H Primary/Secondary Circuit Malfunction
Last updated:
System
Powertrain (Engine & Gearbox)
Related Fault Codes
Technical Description
P0358 indicates that the Engine Control Unit (ECU) has detected an electrical fault in the primary or secondary circuit of the ignition coil for cylinder number 8 ('H'). The ignition system uses an internal driver transistor to ground the coil's primary winding. When the ground is interrupted, the magnetic field disappears, inducing high voltage in the secondary winding. If the ECU fails to detect the expected inductive kick or if the current draw does not meet the target during the dwell period, this DTC is stored. This fault impacts ignition timing, combustion stability, and can lead to catalyst damage due to unburned fuel.
Possible Causes
Faulty ignition coil (internal short or open circuit on cylinder 8)
Damaged wiring harness or loose connection at the coil connector
Faulty spark plugs (high resistance stressing the secondary side)
Failed ECU ignition driver or corrosion in the main harness connector
Symptoms
Recommended Solution
- Visual inspection: Check wiring to cylinder 8 for rodent damage, melted insulation, or oxidation in the connector.
- Basic testing: Verify 12V power supply and ground at the coil connector. Measure primary winding resistance (typically 0.5 – 2.0 Ohms depending on application).
- Component swap: Swap the ignition coil from cylinder 8 to another cylinder. If the fault code follows the coil (e.g., moves to P0351 for cyl 1), the coil is faulty.
- Advanced diagnosis: Use an oscilloscope to monitor the ignition waveform (Dwell time and Burn time). Verify the trigger signal (5V or 12V square wave) from the ECU.
- Action: Replace the ignition coil and inspect the spark plug. Clear codes and perform a test drive.
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.
Do you also have
other fault codes?
See how P0358 connects with your other fault codes. Our advanced analysis tool identifies causal relationships and root causes directly.