What it means
An electrical fault is detected in both the primary and the secondary circuit of ignition coil H. The ECU cannot drive the coil correctly, so the cylinder served by coil H misfires or does not fire at all. Causes: an open or shorted primary control wire, an internal coil winding fault, a failed igniter/driver, or wiring or connector damage at the coil.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Coil H's primary winding receives switched current from the ignition control system to create spark for its assigned cylinder. The control module monitors the coil H primary and secondary circuit response and sets P0358 when it detects an electrical fault that can interrupt that cylinder's spark.
Common causes
Most likely first.
- Ignition coil H failure
- Open, shorted, or damaged coil wiring
- Loose or corroded connector
- Fault in the ignition control driver
Symptoms
- Check engine light on or flashing
- Engine misfire or rough running
- Power loss or hesitation
- Hard starting
How to diagnose it
- Use a scan tool to save freeze-frame data and review misfire counts for the cylinder served by coil H.
- Inspect coil H, its connector, and harness for loose or backed-out pins, corrosion, chafing, and heat damage.
- Check coil H's supply and control wiring for opens or shorts according to the wiring diagram and manufacturer's specification.
- Test the primary and secondary paths of coil H using the manufacturer's procedure.
- If the coil and wiring pass, test the ignition control driver and module connections for coil H.
Common fixes
- Reconnect and secure the coil H connector.
- Repair damaged wiring or connector terminals in the coil H circuit.
- Replace coil H if its winding or secondary path fails testing.
- Repair the coil H driver circuit or replace the control module if testing confirms a failed driver.
Can I keep driving?
Stop driving if there is a severe misfire or flashing check-engine light, as continued misfire can overheat the catalytic converter. If the light is steady and the engine runs smoothly, keep trips short and arrange prompt diagnosis.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.