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2015 KIA FORTE
1.8L I4•FWD•AUTOMATIC•gas•G4NB
1 active safety recall on this vehicle — view recalls🏆Sponsored by Simon-Olivier Ricci
Repairs401Labor496Torque3402Fluid7DTC1080Battery1Maintenance0Recalls1
P3656moderate severityPowertrain

Port and Direct Injection System Imbalance

on 2015 Kia Forte 1.8L I4 · FWD

What this code means

In dual-injection systems (combined port and direct injection), the balance between PFI and GDI fueling is incorrect.

Symptoms

  • Check Engine Light
  • Rough idle
  • Knock or ping under load
  • Poor emissions
  • Fuel economy reduced
  • Cold start misfires

Common causes

  • Port injector partial blockage
  • GDI injector drift
  • Fuel pressure imbalance between systems
  • PCM fuel strategy calibration error
  • Intake runner flap affecting port injection

Diagnostic steps

  1. Compare port vs direct injection fuel trim data
  2. Test individual port injector flow
  3. Test GDI injector flow rates
  4. Monitor knock sensor activity
  5. Check intake runner valve operation

Repair notes

Clean or replace affected injectors. Recalibrate fuel split strategy if software update is available. Check intake runner valves.

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