P0355
Ignition Coil E Primary/Secondary Circuit
Encountering the engine check light code P0355 signifies an explicit mechanical or electrical operational breakdown categorized as "Ignition Coil E Primary/Secondary Circuit". Professional scanner tools usually flag this subsystem loop early on.
Driver's Summary
Your vehicle's computer logged P0355 after detecting a malfunction in the ignition coil e primary/secondary circuit system. Typical symptoms include misfire condition, check engine light, poor gas mileage. This condition is classified as high severity. Prompt diagnosis is essential to prevent cascading damage to related components.
Symptoms
Misfire condition, check engine light, poor gas mileage
Common Causes
- Failed ignition coil E (Cylinder 5)
- Wiring harness issue
- Worn spark plug
- PCM fault
How to Fix
- 1 Replace ignition coil E
- 2 Repair damaged wiring
- 3 Replace spark plug
- 4 Replace engine computer
Technical Explanation
Code P0355 is confirmed when the ECM's diagnostic algorithm detects a parameter deviation that persists across a defined number of consecutive drive cycles. For injector-specific codes, the ECM monitors the injector control circuit voltage drop during each pulse; a shorted or open injector presents a characteristic resistance signature that differs measurably from a healthy unit. The fault remains stored in memory even after the MIL is cleared; it becomes a confirmed DTC after failing two consecutive drive cycles, and the PCM logs a freeze frame record of the engine's exact operating state at the moment of detection.
Is It Safe to Drive?
This fault carries real mechanical risk. The root causes — including failed ignition coil e (cylinder 5) — can trigger a chain reaction of component failures if the vehicle continues to be driven. Have it towed or drive directly to a shop without delay.
Mechanic's Pro Tip
Before replacing any component on P0355, spend 5 minutes inspecting the wiring harness and connector first — corrosion, chafed insulation, and backed-out pins cause the majority of these faults and cost nothing to fix. Use a multimeter to measure voltage drop across the connector pins under load; anything above 0.1V indicates excessive resistance that will cause intermittent failures even after replacing the sensor.
Ignition coil: $80 - $200