Intake Air Control Circuit Malfunction
Table of contents
P1504 MERCURY Possible Causes
- Faulty Idle Air Control Valve
- Idle Air Control Valve harness is open or shorted
- Idle Air Control Valve circuit poor electrical connection
- Faulty Powertrain Control Module (PCM)
How do I fix code P1504 MERCURY?
Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector’s pins.
Cost of diagnosing the P1504 MERCURY code
The cost of diagnosing the P1504 MERCURY code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle’s make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.
When is the code detected
Powertrain Control Module (PCM) has detected an electrical load failure on the Idle Air Control Valve (IACV) circuit.
Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
P1504 MERCURY Description
The Idle Air Control Valve (IACV) valve assembly controls the engine idle speed and provides a dashpot function. The IAC valve assembly meters intake air around the throttle plate through a bypass within the IAC valve assembly and throttle body. The Powertrain Control Module (PCM) determines the desired idle speed or bypass air and signals the IAC valve assembly through a specified duty cycle. The IAC valve responds by positioning the IAC valve to control the amount of bypassed air. The PCM monitors engine RPM and increases or decreases the IAC duty cycle in order to achieve the desired RPM.