OBD codes / P0506
P0506
ModerateIdle Air Control System RPM Lower Than Expected
P0506 is usually drivable, but a low or stalling idle can be inconvenient and occasionally unsafe if the engine quits at a stop. It's low-risk mechanically. Try a throttle-body cleaning (plus an idle relearn) before replacing parts — it resolves a lot of these.
What this code means
At idle the computer holds a target RPM by metering a small amount of air past the throttle — either through an idle air control (IAC) valve on older cars or by nudging the electronic throttle on newer ones. P0506 means idle speed is running LOWER than the target. The most common cause is a dirty throttle body or IAC passage: carbon buildup restricts the idle airflow so the engine idles low or stalls. A failing IAC valve or a heavy accessory load can also cause it. A good throttle-body cleaning fixes many cases.
Symptoms you might notice
- Low or rough idle, sometimes near stalling
- Engine stalls at stops or when coming to a stop
- Idle that dips when accessories (A/C, lights) switch on
- Check-engine light
What it costs to fix
Typical range: $50–$500 · about ~0.3–1.5 hrs of labor
| If the cause is… | Part | Labor |
|---|---|---|
| Throttle body / IAC cleaning | $8–$20 | ~0.3–1 hrs |
| Idle air control (IAC) valve | $30–$150 | ~0.3–1 hrs |
| Throttle body (electronic) | $150–$500 | ~0.5–1.5 hrs |
Cleaning is the cheap first step and often enough — many engines also need an idle relearn afterward. An IAC valve is modest; a full electronic throttle body is the expensive end and only needed if cleaning and the valve don't resolve it.
The price swings on which cause it turns out to be — so confirm the cause before paying. Diagnose P0506 for my exact vehicle →
Frequently asked
Can I drive with P0506?
Usually yes, though a low or stalling idle is annoying and can occasionally catch you off guard at a stop. It isn't mechanically dangerous, so you can drive to get it cleaned or diagnosed.
Will cleaning the throttle body fix P0506?
Often — carbon restricting the idle airflow is the most common cause. Clean the throttle body and IAC passage, then do an idle relearn so the computer recalibrates. If it returns, the IAC valve or throttle body may need replacing.
What is an idle relearn?
After cleaning the throttle body or disconnecting the battery, many cars need to relearn their idle position. It's a short procedure (sometimes just specific key/idle steps, sometimes a scan tool) and skipping it can leave the idle off even after a good cleaning.
How much does it cost to fix P0506?
Often cheap — a can of cleaner and labor. An IAC valve is modest; a new electronic throttle body is the priciest outcome. Clean first before buying parts.
Seeing P0506 on your car? Get a diagnosis specific to your exact year, make and model.
Diagnose P0506 for my vehicleGeneric OBD-II reference. Manufacturer-specific behavior varies — confirm with a scan tool and, for safety-related codes, a professional inspection.