P0508 to P0511, P0518 and P0519: idle air control circuit and closed throttle switch
The circuit of the idle air control valve reads low, high or intermittent, the idle air control system is not performing as it should, or the closed throttle position switch has a fault.
SeverityModerateUsually not urgent today, but it can get worse if left.
Can you keep driving?Drive gently, check it soonWhat does P0508 mean?
On engines with a cable throttle, a small valve lets air bypass the closed throttle plate to hold the idle steady, and a switch tells the computer when the throttle is fully closed. Where P0505 to P0507 report an idle speed that is wrong, these codes point at the valve's wiring and response. Carbon builds up on these valves over time and makes them stick, so the idle can hunt, run too high or let the engine stall when coming to a stop.
What causes P0508?
- An idle air control valve sticking with carbon
- A failed idle air control valve coil or motor
- A damaged wire or a corroded connector at the valve
- A closed throttle switch out of adjustment or failed
- A dirty throttle body upsetting the idle airflow
What to check first for P0508
- Watch whether the idle hunts, runs high or drops when the air conditioning or lights are switched on
- Inspect the idle air control valve's connector and wiring
- Have the throttle body and the valve's air passages cleaned with a suitable cleaner
- Have the valve commanded with a scan tool while the idle speed is watched
Can you drive with P0508?
Usually you can drive to a workshop. If the engine stalls at junctions, keep a little throttle when stopping and avoid heavy traffic, since a stall also loses power steering and brake assistance on many cars.
Clear a code only after the fault is fixed. A code that comes back means the cause is still there, and a warning light left on can hide a second fault behind the first.
Codes on this page
- P0508Idle Air Control System Circuit Low
- P0509Idle Air Control System Circuit High
- P0510Closed Throttle Position Switch
- P0511Idle Air Control Circuit
- P0518Idle Air Control Circuit Intermittent
- P0519Idle Air Control System Performance
Related codes
Checked on · Rafael Soares
These are the generic meanings every manufacturer shares. Each brand adds its own detail, so your car's handbook, its service information and a qualified mechanic have the last word. OdoKeep has no connection with any manufacturer, and the app does not read codes from the car.
