P0506 on Honda: How to Diagnose & Fix
Idle Air Control System RPM Lower Than Expected
1 Honda model · 1 documented issue · $50-$300 repair
P0506 on Honda by model: symptoms, diagnosis and fix
The idle air control valve (IACV) on the throttle body meters the air that bypasses the closed throttle at idle. On D-series Civics it fouls with carbon and the pintle sticks, so the ECU can no longer stabilize idle. Symptoms are a hunting/surging idle, abnormally high idle, or the engine dying when coming to a stop or cold.
Common Symptoms
- Idle hunts up and down at stops
- Stalls when decelerating to a stop or when cold
- Abnormally high idle speed
- Rough shaking idle
- Stalls with A/C or electrical load applied
How to Fix
Remove and clean the IACV and throttle body with carburetor/throttle-body cleaner; replace the IACV if the pintle is stuck or the coil is out of spec. Perform the idle relearn afterward. Clean the associated throttle-body ports (fast-idle thermovalve on older D-series).
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- 1996 Honda Civic genuine idle-control-valve catalogOEMHonda 16022-P2E-A51 / 36450-P2J-J01 / 16022-P2A-J01 by confi
Select exact VIN and do not transfer
- 2001-2005 Honda Civic genuine idle-control-valve catalogOEMHonda 16022-PLC-J01 automatic/CVT / 16022-PLC-003 5MT
Enter VIN because GX, Si and other engine/emissions branche
- Genuine Honda 16176-P2A-004 throttle-body gasketOEMHonda 16176-P2A-004
Do not buy for a cleaning procedure that does not detach the throt
- Genuine Honda 16176-PMR-A01 throttle-body gasketOEMHonda 16176-PMR-A01
Enter VIN because alternate engine/emissions branches exist; do not buy unless the procedure removes the
- CRC 05078 throttle body and air-intake cleaner, 12 ozOEMCRC 05078 / AutoZone SKU 55922
Do not spray or soak the IACV electrical coil/motor, MAF sensor or incompatible c
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Sources for this issue (2)
P0506 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0506 mean on a Honda?
P0506 stands for "Idle Air Control System RPM Lower Than Expected." This code means the engine computer detected that the engine's idle speed is lower than the target idle RPM it commanded. The PCM controls idle speed through the idle air control valve or electronic throttle and sets this code when the actual idle drops below expected. A low or rough idle can cause stalling, hesitation, and reduced drivability. On Honda it is documented across 1 model: Civic.
What are the most common causes of P0506?
The most common causes of P0506 are: Vacuum leak in intake or hoses, Dirty or carbon-clogged throttle body, Faulty idle air control (IAC) valve, Dirty or failing mass airflow sensor, Clogged PCV system or EGR sticking open, Worn or dirty fuel injectors, Excessive engine load from accessories. The specific cause varies by vehicle.
How much does it cost to fix P0506 on a Honda?
Published repair estimates on Honda range from $50 to $300 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.