P0506 means the engine is idling at a lower RPM than the ECU expects, typically 100 RPM or more below target, and the ECU cannot bring it back up. The opposite of P0507, this code is usually caused by carbon buildup on the throttle body restricting airflow, a partially clogged idle air control passage, or a vacuum hose pinched or blocked rather than leaking.
DTC/P0506·Honda
P0506 on Honda: Causes, Symptoms and Fix Cost
Quick Answer
Moderate SeveritySafe to drive (short-term)Honda
P0506 on a Honda means the engine is idling at a lower RPM than the ECU expects, typically 100 RPM or more below target, and the ECU cannot bring it back up. The opposite of P0507, this code is usually caused by carbon buildup on the throttle body restricting airflow, a partially clogged idle air control passage, or a vacuum hose pinched or blocked rather than leaking.
Repair cost on Honda€5 - €495
What does P0506 mean on a Honda?
Honda Civic
2006-2015R18A Civics commonly log P0506 from a clogged IACV. Honda's recommended fix is to remove the valve, clean it with carburettor cleaner, and reset adaptations by disconnecting the battery for ten minutes followed by a ten-minute idle with the AC off.
What causes P0506 on a Honda?
Beyond the generic causes listed on the main P0506 page, these are the Honda-specific patterns we see most often:
Honda CivicIACV carbon clogging on R18A
Honda CivicThrottle body bore deposits on 1.8 SOHC i-VTEC
How to diagnose P0506 on a Honda with OBD2
Follow these steps to pinpoint the root cause of P0506:
- Read freeze-frame data and confirm idle RPM at the time the code set. Compare to the ECU's commanded idle target shown in live data
- Remove the intake boot and inspect the throttle plate and bore for carbon buildup. Heavy deposits restrict airflow even with the plate fully closed
- Clean the throttle body with throttle body cleaner and a soft cloth. On electronic throttle bodies, do not force the plate open by hand; use the scan tool throttle test instead
- If equipped with a separate idle air control valve, remove and clean or test it with the scan tool to verify movement through its full range
- After cleaning, perform the manufacturer's idle relearn procedure. Without a relearn, the ECU continues to command the same restrictive throttle position
How much does P0506 cost to fix on a Honda? (EUR)
Estimated repair costs on a Honda (Honda parts and labour typically run 10% below the average for this code).
Prices estimated as of May 2026. Costs vary by region, vehicle, and shop.
Related codes that often appear with P0506 on Honda
These codes commonly cluster with P0506 on Honda vehicles:
FAQ: P0506 on Honda
Why is my car idling so low?
Carbon buildup on the throttle body or a stuck idle air control valve is the most common cause. The engine cannot pull enough air at idle, the ECU cannot bring RPM up to target, and you feel it as a shaky, sometimes stalling idle.
Will cleaning the throttle body fix P0506?
Often yes, but only if you also perform the idle relearn afterwards. Without the relearn, the ECU keeps commanding the throttle to the position it learned when the bore was dirty, and the symptom returns within a day or two.
Why does my engine stall when the AC turns on?
The AC compressor adds load to the engine at idle. A healthy idle control system raises RPM to compensate. When P0506 is set, the system can no longer pull that extra air, so the engine loses RPM and may stall.
Is P0506 the opposite of P0507?
Yes. P0506 means the engine idles too low; P0507 means it idles too high. Both point to a problem with how the ECU controls idle airflow, but the causes are different. P0506 usually points to restriction; P0507 usually points to a leak or stuck-open valve.
Looking for the full P0506 reference (all makes, full diagnosis flow, complete repair cost matrix)?
See the main P0506 guideSkanyx · Honda
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