P0506: Idle Control System RPM - Lower Than Expected
A generic powertrain (engine and transmission) trouble code, same meaning on every brand.
Yes - low idle can stall at stops, so fix if the engine dies at lights.
Symptoms
- Idle lower than spec
- Stalling when coming to a stop
- Sag when AC engages
Likely causes, most common first
- Throttle body carbon restricting airflow
- Vacuum or intake gasket leak confusing control
- IAC passage clogged on cable throttles
Read P0506 yourself before paying for diagnosis
A basic Bluetooth OBD-II scanner ($20-40) plugs into the port under the dashboard and shows this code with live sensor data on your phone - useful both for confirming the fix and for talking to a shop from an informed position.
What is going on and how it gets diagnosed
P0506 means idle rpm is stuck below target even with the computer commanding more air. Carbon buildup is the usual thief - it narrows the throttle's idle passage until control authority runs out.
Cleaning plus the relearn procedure fixes most cases. Stalling at stops moves this from cosmetic to genuine driveability territory - do not sit on it for months.
Repair options and cost
Typical US independent-shop ranges, parts and labor. Dealers run higher; regional labor rates vary.
Owner reports mentioning P0506
“I keep getting a check engine light with my Pacifica hybrid. The scanner says P1B11, soft code is P0506, Hybrid battery or wiring harness. The codes erase after driving for a long while, however, I notice that I'm not able to maintain a full hybrid battery charge for longer than a few miles. After about 5 miles of driving, I'm a 80% of battery life left. MPG averages about 30+/- something's not right. It's happened twice now, both times with excessive outside temperatures. 1st time while idling, 2nd time while stopped for fueling.”2018 Chrysler Pacifica · Jul 2024
“Oil pressure change indicated on dashboard stating, "low oil pressure", the indicator then went out and the 2012 vw cc 2.0 tsi shut off while driving on the interstate at a speed of approximately 45 miles a hour. The vehicle was restarted and moved of the interstate under its own power, but was idling rough and stalled. The vehicle will not start now. The code pulled from this vehicle now read, p0300, p0302, p0341, p000a, p0016, p0304, p0301, p0011, p0506”2012 Volkswagen CC · Sep 2020 · 77,000 mi
“I was driving at the time of failure. Engine light comes on and I took it to the shop to run a diagnostics. These are the codes p0106, p0300 and p0506 that are causing the engine light to keep coming on. This is the second time this has happen. First time the parts replaced were oxygen sensor and the computer back in dec 2005. Now its feb 2006 and I need to take it in again for same problem. *jb”2005 GMC Canyon · Dec 2005 · 64,100 mi
Cars that report P0506 most often
Based on mentions of this code in NHTSA owner complaints.
Frequently asked questions
Can I drive with P0506?
Yes - low idle can stall at stops, so fix if the engine dies at lights.
How much does it cost to fix P0506?
Typical US repair costs range from $80 for the simplest fix (throttle body cleaning + relearn) to $400 in the worst case. The right number depends on which cause your car has - see the causes list.
Definition per SAE J2012 standard nomenclature. Symptoms, causes and costs are editorial guidance - always confirm with a diagnosis of your specific vehicle.