Ignition Coil H Primary/Secondary Circuit Malfunction
P0358 indicates a malfunction in the ignition coil H (coil on plug) primary or secondary circuit. The engine control module has detected an electrical fault in the coil driver circuit or the coil itself, preventing proper ignition timing for that cylinder.
What You Might Notice
- Check Engine Light (MIL) illumination
- Engine misfire on cylinder H
- Rough idle or stumbling during acceleration
- Loss of power or reduced fuel economy
- Intermittent misfire conditions
Most Common Causes
- 1
Faulty Ignition Coil
The coil on plug (COP) ignition coil H has failed internally or has a short/open circuit. This is the most common cause and requires direct coil replacement.
- 2
Loose or Corroded Connector
The coil connector is loose, corroded, or has broken connector locks preventing proper electrical contact. Cleaning or reseating the connection often resolves this issue.
- 3
Wiring Harness Short or Open
The COP driver circuit wiring has a short to voltage/ground or an open circuit break. Damaged insulation or severed wires disrupt the signal between the PCM and coil.
- 4
Faulty Powertrain Control Module
The PCM coil driver circuit has failed, preventing proper signal output to coil H. This is rare but requires PCM reprogramming or replacement.
How to Diagnose It
- 1
Check Faulty Ignition Coil — The coil on plug (COP) ignition coil H has failed internally or has a short/open circuit. This is the most common cause and requires direct coil replacement.
- 2
Check Loose or Corroded Connector — The coil connector is loose, corroded, or has broken connector locks preventing proper electrical contact. Cleaning or reseating the connection often resolves this issue.
- 3
Check Wiring Harness Short or Open — The COP driver circuit wiring has a short to voltage/ground or an open circuit break. Damaged insulation or severed wires disrupt the signal between the PCM and coil.
- 4
Check Faulty Powertrain Control Module — The PCM coil driver circuit has failed, preventing proper signal output to coil H. This is rare but requires PCM reprogramming or replacement.
How to Fix It
- 1
Replace Ignition Coil H
Remove the faulty coil on plug unit from cylinder H and install a new OEM or quality aftermarket coil. Ensure the connector is fully seated and secure.
- 2
Clean and Reseat Coil Connector
Disconnect the coil H connector, inspect for corrosion or debris, clean the terminals with electrical contact cleaner, and firmly reseat the connection to restore proper contact.
- 3
Inspect and Repair Wiring Harness
Trace the COP driver circuit wiring from the coil to the PCM, looking for cuts, fraying, or corrosion. Repair damaged sections by splicing and sealing with heat shrink tubing or replace the entire harness if severely damaged.
- 4
Check PCM and Reprogram if Needed
If all coils, connectors, and wiring test normal, the PCM may require reprogramming or replacement. Have the vehicle scanned with advanced diagnostics to confirm PCM failure before proceeding.
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