Idle Air Control Circuit Malfunction
2012-2020 Ford Focus 2.0L I4
Description
The Idle Air Control (IAC) valve circuit has a malfunction. The IAC valve controls engine idle speed by regulating the amount of air bypassing the throttle plate.
Symptoms
- Check Engine Light
- Erratic idle speed
- Idle too high or too low
- Engine stalling at idle
- Rough idle
Common Causes
- Faulty IAC valve
- Carbon buildup on IAC valve or throttle body
- Wiring issue to IAC
- Vacuum leak affecting idle
- Dirty throttle body
Diagnostic Steps
- Test IAC valve resistance
- Clean IAC valve and throttle body
- Inspect IAC wiring and connector
- Check for vacuum leaks
- Monitor IAC duty cycle on scan tool (should be 22-65%)
Repair Notes
Clean throttle body and IAC valve first. Replace IAC if faulty. Repair vacuum leaks.
Related Codes
Other Powertrain Codes
- P0001Fuel Volume Regulator Control Circuit/Open
- P0002Fuel Volume Regulator Control Circuit Range/Performance
- P0003Fuel Volume Regulator Control Circuit Low
- P0004Fuel Volume Regulator Control Circuit High
- P0010Intake Camshaft Position Actuator Circuit/Open Bank 1
- P0011Intake Camshaft Position Timing Over-Advanced Bank 1
- P0012Intake Camshaft Position Timing Over-Retarded Bank 1
- P0013Exhaust Camshaft Position Actuator Circuit/Open Bank 1
- P0014Exhaust Camshaft Position Timing Over-Advanced Bank 1
- P0015Exhaust Camshaft Position Timing Over-Retarded Bank 1
P1504 on Other Vehicles
Common Questions
What does code P1504 mean on a 2012-2020 Ford Focus?
P1504 stands for "Idle Air Control Circuit Malfunction". The Idle Air Control (IAC) valve circuit has a malfunction. The IAC valve controls engine idle speed by regulating the amount of air bypassing the throttle plate.
What are the symptoms of P1504 on a Ford Focus?
Common symptoms of P1504 include: Check Engine Light, Erratic idle speed, Idle too high or too low, Engine stalling at idle, Rough idle.
What causes P1504 on a 2012-2020 Ford Focus?
Common causes of P1504 include: Faulty IAC valve, Carbon buildup on IAC valve or throttle body, Wiring issue to IAC, Vacuum leak affecting idle, Dirty throttle body.