Idle Control System Malfunction Fail Safe
1997-2001 Subaru Impreza 2.2L H4
Description
The PCM has entered failsafe mode for the idle control system. The idle speed control cannot maintain target idle and has exceeded the correction range, triggering a failsafe idle speed that may be higher or lower than normal.
Symptoms
- Check Engine Light
- Idle speed fixed at failsafe value
- Rough or unstable idle
- Engine may stall
- Poor idle quality
Common Causes
- Large vacuum leak
- Faulty idle air control valve
- Dirty throttle body restricting airflow
- Carbon buildup in IAC passages
- Intake manifold gasket leak
Diagnostic Steps
- Perform smoke test for vacuum leaks
- Clean throttle body and IAC passages
- Test IAC valve operation
- Check intake manifold gaskets
- Monitor IAC duty cycle on scan tool
Repair Notes
Locate and repair vacuum leaks; clean the throttle body and IAC system.
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
P1507 on Other Vehicles
Common Questions
What does code P1507 mean on a 1997-2001 Subaru Impreza?
P1507 stands for "Idle Control System Malfunction Fail Safe". The PCM has entered failsafe mode for the idle control system. The idle speed control cannot maintain target idle and has exceeded the correction range, triggering a failsafe idle speed that may be higher or lower than normal.
What are the symptoms of P1507 on a Subaru Impreza?
Common symptoms of P1507 include: Check Engine Light, Idle speed fixed at failsafe value, Rough or unstable idle, Engine may stall, Poor idle quality.
What causes P1507 on a 1997-2001 Subaru Impreza?
Common causes of P1507 include: Large vacuum leak, Faulty idle air control valve, Dirty throttle body restricting airflow, Carbon buildup in IAC passages, Intake manifold gasket leak.