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DTC codes / Kia codes / P1507

P1507 · KiaIdle Air Control Valve Closing Coil Voltage Low

P1507 on Kia vehicles means the engine control module (ECM) has detected that the voltage on the closing coil circuit of the idle air control (IAC) valve is lower than expected. The ECM monitors this circuit and sets the code when the signal indicates an open, short to ground, or excessive resistance in the coil or its wiring.

SystemPowertrain
Code typeKia specific
SeverityMedium
Fix difficultyIntermediate
AreaVehicle speed, idle control and auxiliary inputs

Symptoms you may notice

  • Check engine light illuminated on the dashboard
  • Rough or erratic idle, sometimes stalling when coming to a stop
  • Engine may idle too high or too low depending on valve position
  • Hesitation or stumble on acceleration from idle
  • Often no symptoms besides the warning light, especially if the valve is stuck in a default position

Common causes, most likely first

  1. Faulty idle air control valve closing coil (open or shorted internally)
  2. Damaged or corroded electrical connector at the IAC valve
  3. Broken, chafed, or shorted wire in the closing coil circuit
  4. Poor ground connection for the IAC valve or ECM
  5. Failed engine control module (ECM) driver for the closing coil
  6. Carbon buildup or mechanical binding inside the IAC valve causing abnormal current draw

How to diagnose and fix it

  1. Scan all modules and record freeze-frame data to confirm P1507 is the only idle-related code
  2. Inspect the IAC valve connector and wiring for corrosion, loose pins, or damage
  3. Measure resistance of the closing coil at the valve and compare to factory specification
  4. Check for short to ground or open circuit in the closing coil wires between the IAC valve and ECM
  5. Verify good ground and power supply to the IAC valve and ECM
  6. If wiring and resistance are within spec, test the ECM driver with a known-good IAC valve or oscilloscope
  7. Replace the faulty IAC valve or repair wiring as needed, then clear codes and perform an idle relearn

Before replacing the idle air control valve

  • A low voltage reading on the closing coil often comes from a poor connection at the IAC valve connector rather than a failed valve, so always inspect the pins and terminals first.
  • Carbon buildup inside the IAC valve can cause the closing coil to draw excessive current, which the ECM interprets as low voltage, leading to unnecessary valve replacement.
  • The ECM may set P1507 intermittently if the closing coil circuit is only marginally out of specification, so wiggle-testing the harness while monitoring live data is a reliable way to catch it.
  • On some Kia models, a weak battery or charging system fault can cause low voltage codes across multiple circuits, including P1507, so check system voltage before condemning the IAC valve.
  • Replacing the IAC valve without performing an idle relearn procedure can leave the engine idling poorly even after a correct repair.

Can I keep driving with P1507?

You can usually drive the vehicle with P1507, but expect rough idling and possible stalling at low speeds, so avoid heavy traffic and keep engine loads light until repaired. If the engine stalls frequently or idles very high, have it checked promptly to prevent safety issues.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for Kia vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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