Ignition

P0358 — Ignition Coil H Circuit Malfunction (Cylinder 8)

Severity: medium Drive with care, to a shop

What P0358 means

The engine control module drives ignition coil H, which normally fires cylinder 8, and monitors the coil circuit. P0358 is set when the signal does not match what is expected, for example due to an open, a short, or a failing driver. As a result, that cylinder may get a weak spark or none.

Symptoms

  • Check Engine light on (flashing if the misfire is severe)
  • Rough idle
  • Misfire on cylinder 8
  • Hesitation or reduced power
  • Higher fuel consumption
  • Engine vibration

Possible causes

  1. Failed ignition coil H (cylinder 8)
  2. Open or shorted wiring to the coil
  3. Corroded or loose coil connector
  4. Worn or faulty spark plug in cylinder 8 stressing the coil
  5. Missing power or ground supply to the coil circuit
  6. Faulty coil driver inside the ECM (rare)

How to diagnose

  1. Read all codes and freeze frame data, and check per-cylinder misfire counts
  2. Confirm which cylinder coil H serves using the wiring diagram for your engine
  3. Inspect the coil connector and harness for corrosion, heat damage, chafing, or oil
  4. Swap coil H with a neighboring coil, clear the code, and see whether the fault follows the coil
  5. Pull the cylinder 8 spark plug and check gap, wear, and fouling
  6. Use a multimeter to check power, ground, and the control signal at the coil connector
  7. Measure coil winding resistance and compare it with specifications
  8. If the circuit is good, test the ECM driver

Common fixes

  • Replace ignition coil H
  • Replace the cylinder 8 spark plug (ideally the whole set)
  • Repair the wiring harness or replace the connector
  • Clean the contacts and restore power and ground to the circuit
  • Replace or reprogram the ECM only if confirmed faulty (rare)

P0358 on different brands

Ford · manuals
On Ford, P0358:11 in the 2024-2025 gasoline monitor strategy indicates a short to ground in the coil control circuit; it describes the detected monitor condition, not a confirmed failed part.

Questions and answers

Can I drive with a P0358 code?

Only briefly and carefully, and not if the check engine light is flashing. Misfires can damage the catalytic converter, so don't put off the repair.

What most often causes P0358?

Usually the cylinder 8 ignition coil itself, or a problem in its connector or wiring. Check those first, then the spark plug.

Is clearing the code enough?

No. If the cause remains, the code will come back. Find the fault first, for example by swapping coils and testing the circuit.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.