P1506moderate severityPowertrain
Idle Air Control Overspeed Error
on 2016 Lincoln MKX 3.7L V6 · AWD
What this code means
The engine idle speed is too high. The PCM has detected that idle RPM exceeds the target idle speed and the IAC system cannot bring it down. The engine may be idling at 2000+ RPM.
Symptoms
- Check Engine Light
- Idle speed too high
- Engine races at idle
- Vehicle creeps forward in gear
Common causes
- Vacuum leak (most common)
- IAC valve stuck open
- Throttle plate not closing fully
- Throttle body carbon buildup preventing closure
- Faulty IAC valve
- Intake manifold gasket leak
Diagnostic steps
- Check for vacuum leaks with engine running — spray carb cleaner around intake
- Inspect throttle body for carbon preventing plate closure
- Test IAC valve — disconnect and check if idle drops
- Clean throttle body and IAC passages
- Inspect intake manifold gaskets
Repair notes
Find and repair vacuum leak. Clean throttle body. Replace IAC valve if stuck open.
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Other Powertrain codes on this vehicle
P0001
Fuel Volume Regulator Control Circuit/Open
P0001
Fuel Volume Regulator Control Circuit/Open
P0002
Fuel Volume Regulator Control Circuit Range/Performance
P0002
Fuel Volume Regulator Control Circuit Range/Performance
P0003
Fuel Volume Regulator Control Circuit Low
P0003
Fuel Volume Regulator Control Circuit Low
P0004
Fuel Volume Regulator Control Circuit High
P0004
Fuel Volume Regulator Control Circuit High
P0010
Intake Camshaft Position Actuator Circuit/Open Bank 1
P0010
Intake Camshaft Position Actuator Circuit/Open Bank 1