P0507 Chevy Silverado: Idle Air Control High RPM Fix

P0507 on a Chevy Silverado means the ECM has detected that idle speed is higher than the target — the idle control system is reading higher RPM than commanded. On 4.8L, 5.3L, and 6.0L Vortec trucks, this typically points to a vacuum leak or a dirty throttle body.

What P0507 Means

Modern GM trucks control idle speed by adjusting throttle plate position through the electronic throttle control (ETC) system. When the ECM commands a specific idle RPM but the actual idle is significantly higher, P0507 is stored. The ECM is trying to close down the throttle but idle stays high — meaning air is getting in somewhere it shouldn’t be, or the throttle body itself is dirty enough to hold the throttle plate open slightly.

Most Common Causes on Silverado/Sierra

P0507 on 4.8L/5.3L/6.0L trucks is most commonly caused by: a dirty throttle body with carbon buildup holding the blade slightly open, a vacuum leak anywhere in the intake manifold or hoses, a leaking intake manifold gasket, or a failed idle air control (IAC) valve on older TBI-equipped OBS trucks (GMT400, pre-2000). On GMT800 and newer trucks with electronic throttle, a dirty throttle body is the first thing to check.

Throttle Body Cleaning Procedure

Disconnect the air intake tube from the throttle body. With the engine off, spray throttle body cleaner on a clean rag and wipe out carbon deposits from around the throttle plate and bore. Do NOT use excessive spray directly into the throttle — it can damage the TPS sensor coating. Clean, reinstall, clear the code, and perform a throttle body relearn procedure by letting the truck idle for 5–10 minutes without touching the accelerator.

If Cleaning Doesn’t Fix P0507

Check all vacuum lines visually and with a smoke machine if available. Listen for hissing near the intake manifold with the engine running. Check the brake booster vacuum line (a cracked booster line is a common P0507 cause on GMT800/GMT900 trucks). Also check the crankcase vent hose connecting the valve cover to the throttle body or intake.