P1505 — BMW — Idle Speed Control Valve Closing Solenoid Control Circuit Electrical

P1505 (BMW): Idle Speed Control Valve Closing Solenoid Control Circuit Electrical — what it means, the affected system and what to check before replacing parts.

Meaning, symptoms, causes and checks

Idle Speed Control Valve Closing Solenoid Control Circuit Electrical. Source catalogue definition; confirm applicability using vehicle service information.

Affected system: Powertrain

Symptoms

  • Unstable or erratic idle speed
  • Engine stalling at stop signs or traffic lights
  • High engine idle RPM
  • Engine failing to maintain idle speed during cold starts
  • Illuminated Check Engine light

Possible causes

  • Faulty Idle Air Control (IAC) valve solenoid
  • Open or short circuit in the IAC valve wiring harness
  • Corroded or loose electrical connector at the IAC valve
  • Failed ECU driver circuit for the IAC valve
  • Binding or seized IAC valve mechanical assembly

What to check

  • Inspect the electrical connector at the IAC valve for corrosion or bent pins
  • Test the wiring harness between the ECU and the IAC valve for continuity and resistance
  • Measure the resistance of the IAC valve solenoid coil using a multimeter
  • Check for battery voltage supply to the IAC valve connector with the ignition on
  • Verify proper operation of the IAC valve actuator by performing an active test with a scan tool