P0507moderate severityPowertrain
Idle Air Control System RPM Higher Than Expected
on 1998 Lexus SC 300 3.0L I6 · RWD
What this code means
The idle speed is consistently above the target RPM.
Symptoms
- High idle speed
- Engine racing at idle
Common causes
- Vacuum leak (most common)
- IAC valve stuck open
- Throttle plate not closing fully
- Intake gasket leak
Diagnostic steps
- Check for vacuum leaks
- Inspect throttle plate
- Test IAC valve
- Check intake gaskets
Repair notes
Find and fix vacuum leak. Clean throttle body. Replace IAC if stuck open.
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