Idle RPM below target.
P0506 — also written PO5O6, P 0506, 0506 — is the OBD-II code for idle speed lower than expected. Same code, same fix: this page covers every spelling of it.
Your engine's tick-over is dropping too low, making it feel like it's about to stall at the lights—usually because the 'throat' of the engine is choked with carbon or air is leaking in where it shouldn't. Very common on older Fiestas and the VW Group 1.2/1.4 petrol units.
P0506 is a engine fault code, typically costing £60–£400 to put right in a UK garage.
What P0506 actually feels like to drive
- The car feels like it wants to 'die' at traffic lights or roundabouts.
- A rough, chugging vibration through the steering wheel when sitting at idle.
- The engine 'hunts' (RPM needle bounces up and down) before settling too low.
- Stalling immediately after a cold start unless you give it some 'welly'.
- The car feels like it’s about to stall specifically when the Air Con is turned on.
What causes P0506?
- Vacuum leak
- Throttle body dirty
- Idle control fault
UK vehicles that throw P0506 most often
- Ford Fiesta 1.25/1.4 Zetec (2008-2017)
- Volkswagen Polo/Golf 1.2 & 1.4 TSI (2009-2015) - Engine codes CBZA/CBZB
- Vauxhall Corsa D/E 1.2 & 1.4 (A12XER/A14XER)
- Nissan Qashqai 1.6 Petrol (HR16DE) 2007-2013快速
- Honda Civic 1.8 i-VTEC (2006-2011) - Common dirty throttle plate issue.
- Skoda Fabia 1.2 HTP (3-cylinder models)
How P0506 is fixed
- Smoke test
- Throttle body clean
The P0506 misdiagnosis that wastes money
The biggest mistake I see is lads jumping straight to replacing the Idle Air Control (IAC) valve or the entire throttle body assembly. It’s an easy win for them to parts-cannon a £150 sensor at the car, but nine times out of ten, that's not the issue. Most of the time, the throttle plate is just choked with carbon deposits or there's a tiny vacuum leak on a perished breather pipe that's tricking the ECU. Cleaning the throttle body costs a fiver in solvent and half an hour of labour, yet people still waste hundreds on new parts that don't fix the hunting idle.
What a UK garage should charge for P0506
A standard diagnostic plug-in and throttle body clean usually runs between £80 and £120 at an independent like mine. If we find a split vacuum hose, you’re looking at maybe £30 for a genuine part plus an hour's labour. However, if the electronic throttle motor has actually burnt out—rare, but happens—a Bosch or Pierburg replacement part can be £200-£300, plus another £60 for fitting and coding. Main dealers will easily double these prices with their £150+ hourly rates and 'genuine' boxed markups.
P0506 repair cost in the UK
Most P0506 repairs land between £60–£400 including parts and labour. The spread is wide because the cheap fix (a sensor, a hose, a leak) and the expensive fix (a major component) throw the same code — which is why a proper diagnosis before parts are bought saves the most money.
Bob's tip on P0506
If a garage tells you that you need a brand-new throttle body for £400, ask them if they’ve 'performed a throttle body adaptation' or 'reset the idle learn' after cleaning it. On modern VAG or Ford engines, if you clean the gunk off but don't tell the ECU it’s clean, it’ll still try to compensate for the old blockage and the code will stay. Also, insist on a smoke test to check for vacuum leaks—it's the only way to find a hairline crack in a plastic intake manifold that only opens up when the engine’s warm. If they won't do these basic steps, take your car elsewhere.
Can you drive with P0506?
Drivable.
Urgency: low.