P1505moderate severityPowertrain
Idle Air Control System at Adaptive Limit
on 2004 Ford Taurus 3.0L V6 Duratec · FWD
What this code means
The IAC system has reached its maximum adaptive correction and can no longer maintain proper idle speed. This indicates the IAC is working at its limit trying to compensate for another issue.
Symptoms
- Check Engine Light
- Idle speed too high or too low
- Rough idle
- Stalling
Common causes
- Large vacuum leak
- Carbon buildup restricting airflow
- Faulty IAC valve
- Throttle body needs cleaning
- Air leak in intake system
Diagnostic steps
- Check for vacuum leaks using smoke test
- Clean throttle body and IAC passage
- Monitor IAC duty cycle — near 0% or 100% indicates problem
- Inspect for air leaks in intake system
Repair notes
Find and fix the root cause (usually vacuum leak or carbon buildup). Clean throttle body. Replace IAC if valve itself is faulty.
Other Powertrain codes on this vehicle
P0001
Fuel Volume Regulator Control Circuit/Open
P0002
Fuel Volume Regulator Control Circuit Range/Performance
P0003
Fuel Volume Regulator Control Circuit Low
P0004
Fuel Volume Regulator Control Circuit High
P0010
Intake Camshaft Position Actuator Circuit/Open Bank 1
P0011
Intake Camshaft Position Timing Over-Advanced Bank 1
P0012
Intake Camshaft Position Timing Over-Retarded Bank 1
P0013
Exhaust Camshaft Position Actuator Circuit/Open Bank 1
P0014
Exhaust Camshaft Position Timing Over-Advanced Bank 1
P0015
Exhaust Camshaft Position Timing Over-Retarded Bank 1