Ignition Coil E Primary/Secondary Circuit Malfunction
P0355 indicates the powertrain control module detected a malfunction in ignition coil E's primary or secondary circuit. This prevents proper spark generation at that cylinder, causing misfires and reduced engine performance. The fault may be electrical (wiring/connections) or the coil itself may be faulty.
What You Might Notice
- Check Engine Light (MIL) illumination
- Engine misfire, especially on cylinder E
- Rough idle or stumbling acceleration
- Loss of power or reduced fuel economy
- Intermittent starting difficulty
Most Common Causes
- 1
Faulty Ignition Coil (COP)
The coil on plug ignition coil E has failed internally or has open windings. This is the most common cause and requires coil replacement.
- 2
Loose or Corroded Coil Connector
The electrical connector at coil E is loose, corroded, or has broken connector locks. This breaks the circuit between the PCM and coil.
- 3
Wiring Short or Open Circuit
The primary or secondary circuit wiring has shorted to voltage/ground or has an open break. This prevents proper coil driver signal from the PCM.
- 4
Faulty Powertrain Control Module (PCM)
The PCM's coil driver circuit is defective and cannot properly command ignition coil E. This is less common and typically diagnosed after other causes are ruled out.
How to Diagnose It
- 1
Check Faulty Ignition Coil (COP) — The coil on plug ignition coil E has failed internally or has open windings. This is the most common cause and requires coil replacement.
- 2
Check Loose or Corroded Coil Connector — The electrical connector at coil E is loose, corroded, or has broken connector locks. This breaks the circuit between the PCM and coil.
- 3
Check Wiring Short or Open Circuit — The primary or secondary circuit wiring has shorted to voltage/ground or has an open break. This prevents proper coil driver signal from the PCM.
- 4
Check Faulty Powertrain Control Module (PCM) — The PCM's coil driver circuit is defective and cannot properly command ignition coil E. This is less common and typically diagnosed after other causes are ruled out.
How to Fix It
- 1
Replace Ignition Coil E
Remove the failed coil on plug unit from cylinder E and install a new OEM or quality replacement coil. Verify proper seating and connector engagement.
- 2
Inspect and Repair Coil Connector
Check the coil E connector for corrosion, bent pins, or broken locks. Clean corrosion with electrical contact cleaner or replace the connector assembly. Ensure the connector seats fully.
- 3
Test and Repair Coil Circuit Wiring
Using a multimeter, test the primary and secondary coil circuits for continuity and shorts. Repair any damaged wiring, splice connections, or ground faults. Consult the vehicle wiring diagram for proper circuit paths.
- 4
Diagnose PCM Coil Driver Circuit
If all coil, connector, and wiring checks pass, test the PCM coil driver output with a scope or specialized diagnostic tool. A faulty PCM driver circuit requires module reprogramming or replacement by a dealer.
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