P0506 on GMC
Idle Air Control System RPM Lower Than Expected
P0506 on GMC vehicles indicates idle air control system rpm lower than expected. Au7o has documented this code across 1 GMC model — most commonly on Terrain. 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.
Common Causes of P0506
- •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
P0506 on GMC by Model
GMC Terrain(1 issue)
- Charge Air Cooler Outlet Duct Disconnecting at the Throttle Body - Sudden Power Loss and Stall2018-2022
On 1.5L LYX-equipped Terrains the charge air cooler outlet tube can separate from the throttle body inlet. The retaining clip design does not hold the duct under boost pressure and heat cycling, so the tube pops off, dumping boost and unmetered air. GM issued Service Update N192266090 covering the charge air cooler duct disconnect at the throttle body on 2019 Malibu, Equinox and Terrain 1.5L vehicles, and the condition is further covered by field bulletins PIP5651 and 22-NA-224 across the 2018-2022 range. This is separate from the frozen-CAC condition: the cooler is fine, the connection has come apart. It is also distinct from the throttle body / TPS electrical failure already documented, because the fault is mechanical air-path separation.
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View P0506 across all makes →Frequently Asked Questions
What does P0506 mean on GMC?▼
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 GMC specifically, this code is documented across 1 model.
What causes P0506 on GMC vehicles?▼
Common causes on GMC: 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. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0506 on a GMC?▼
Repair costs vary widely depending on the root cause and specific GMC model.
Which GMC models have P0506 documented?▼
Au7o has documented P0506 on 1 GMC model: Terrain.