Ignition Coil I Primary/Secondary Circuit Malfunction
P0359 indicates a malfunction in the primary or secondary circuit of ignition coil I (cylinder 1), which generates the high-voltage spark needed for combustion. The PCM detected an electrical problem in the coil's control circuit, such as a short, open, or poor connection that prevents proper ignition function.
What You Might Notice
- Check Engine Light (MIL) illumination
- Engine misfire on cylinder 1
- Rough idle or hesitation during acceleration
- Loss of power or reduced fuel economy
- Intermittent starting difficulty
Most Common Causes
- 1
Faulty Ignition Coil (COP)
The coil on plug unit for cylinder 1 has failed internally or developed a short/open circuit. This is the most common cause of P0359.
- 2
Loose or Damaged Connector
The electrical connector to the coil is corroded, loose, or has broken locking tabs preventing proper circuit contact.
- 3
Short or Open in Coil Driver Circuit
Wiring between the PCM and ignition coil has shorted to voltage/ground or developed an open break in the circuit.
- 4
Faulty Powertrain Control Module (PCM)
The PCM's coil driver circuit is defective and cannot properly control the ignition coil. This is rare but possible after ruling out other causes.
How to Diagnose It
- 1
Check Faulty Ignition Coil (COP) — The coil on plug unit for cylinder 1 has failed internally or developed a short/open circuit. This is the most common cause of P0359.
- 2
Check Loose or Damaged Connector — The electrical connector to the coil is corroded, loose, or has broken locking tabs preventing proper circuit contact.
- 3
Check Short or Open in Coil Driver Circuit — Wiring between the PCM and ignition coil has shorted to voltage/ground or developed an open break in the circuit.
- 4
Check Faulty Powertrain Control Module (PCM) — The PCM's coil driver circuit is defective and cannot properly control the ignition coil. This is rare but possible after ruling out other causes.
How to Fix It
- 1
Replace Ignition Coil I
Remove the failed coil on plug unit from cylinder 1 and install a new OEM or equivalent replacement coil. Ensure the connector locks properly and there is no debris in the socket.
- 2
Inspect and Repair Coil Connector
Check the connector pins for corrosion or damage, clean with electrical contact cleaner, and ensure the connector locks are intact. Replace the connector or repair wiring if damaged.
- 3
Test and Repair Coil Driver Wiring
Use a multimeter to check continuity and resistance in the wiring harness between the PCM and ignition coil. Repair any damaged wiring or replace the harness if necessary.
- 4
Test or Replace PCM
If all coil and wiring components test normal, the PCM coil driver circuit may be faulty. Have the PCM tested by a professional or replace if confirmed defective.
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