Idle speed higher than expected on Mini — N12/N14/N18 Prince engine vacuum leak from PCV.
Mini P0507 — Idle speed higher than expected on Mini — N12/N14/N18 Prince engine vacuum leak from PCV. Typical UK independent garage cost: £180–£580.
What actually causes P0507 on a Mini
Mini Prince engine P0507 — PCV diaphragm in the rocker cover. Whole rocker cover replacement is the proper fix.
Mini engines that log P0507
- N12/N14 1.6 (R56)
- N18 1.6 (R56/R60)
- B38 1.5 (F56)
How we diagnose P0507 on a Mini
- Smoke-test intake
- Oil filler suction test
- Whole rocker cover replacement
The common misdiagnosis to avoid
Mini dealer pricing is brutal — independent BMW specialist saves 40%.
Mini P0507 repair cost in the UK
Expect £180–£580 including parts and labour at an independent garage. Main-dealer quotes on Mini are usually higher for the same job, and the spread exists because the cheap cause and the expensive cause throw the same code — pay for the diagnosis before you pay for parts.
Bob's workshop tip
Mini Cooper P0507 — rocker cover with PCV. £280 part trade.
Codes usually seen alongside P0507 on Mini
- P0171
- P1004
Symptoms drivers report with P0507
- The car feels like it's 'creeping' forward too fast at traffic lights without touching the gas.
- Engine revs stay hung up at 1200rpm when you dip the clutch approaching an intersection.
- A noticeable 'hissing' or whistling noise from the engine bay when idling on the driveway.
- The stop-start system has stopped working because the idle isn't stable enough for the ECU.
- Surging or 'hunting' revs when you first start it from cold in the morning.
Repairs that clear P0507
- Smoke-test intake
- Clean throttle body
- Replace PCV valve / rocker cover
- Inspect all vacuum hoses
For the generic, all-makes explanation of this code — meaning, every known cause and UK cost bands — see our P0507 guide.