MAP sensor / boost sensor range on BMW N20/N55/N47 — Bosch boost pressure sensor in the charge pipe fails, or charge pipe itself cracks.
BMW P0106 — MAP sensor / boost sensor range on BMW N20/N55/N47 — Bosch boost pressure sensor in the charge pipe fails, or charge pipe itself cracks. Typical UK independent garage cost: £140–£580.
What actually causes P0106 on a BMW
BMW N55 is famous for cracked plastic charge pipes (between intercooler and throttle body) — when they go, the boost sensor reads correctly but doesn't match commanded boost, P0106 stores alongside P0299. On N20 the integrated MAP/IAT sensor in the inlet manifold fails by 50k miles. On N47 diesel the charge pipe leaks at the rubber-to-plastic joint.
BMW engines that log P0106
- N20 2.0 turbo (F30 320i/328i, F10 528i)
- N55 3.0 turbo (335i, 535i, X5)
- N47 2.0d (320d, 520d, X1, X3)
How we diagnose P0106 on a BMW
- INPA — log boost sensor voltage vs commanded boost
- Inspect plastic charge pipe (N55) and rubber elbows (N20/N47) for cracks
- Pressure-test intake system at 15 PSI to find leaks
- Replace MAP sensor on N20 if engine over 50k miles
- Recommend metal aftermarket charge pipe on N55 as the long-term fix
The common misdiagnosis to avoid
Avoid the dealer 'boost system rebuild' quote of £800+ on N55 — a metal upgrade charge pipe (£90 aftermarket) plus a sensor swap fixes 95% of N55 P0106 cases for under £200.
BMW P0106 repair cost in the UK
Expect £140–£580 including parts and labour at an independent garage. Main-dealer quotes on BMW 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
If a customer's bringing in their N55 with P0106 plus the classic 'whoosh' under acceleration, just sell them the metal charge pipe upgrade first — it's the right answer 90% of the time and saves a return visit when the original plastic finally lets go.
Codes usually seen alongside P0106 on BMW
- P0299
- P11AB
- P0238
Symptoms drivers report with P0106
- Sudden loss of power on a motorway slip road — car drops into limp mode at exactly the point you plant the throttle
- Full power returns after a key-off / key-on cycle, then disappears again 10–20 miles later
- Whistling, hissing or a chuff-chuff noise from the engine bay under acceleration
- Slight oil mist around intercooler pipework or a stain on the underside of the bonnet
- MPG drops 4–8 mpg within a tankful, sometimes with faint black smoke on hard acceleration
- Sometimes paired with P0299 (underboost), P0234 (overboost), or P0401 (EGR flow)
Repairs that clear P0106
- Clean or replace MAP sensor
- Smoke-test intake and boost pipes
- Check EGR isn't stuck open
For the generic, all-makes explanation of this code — meaning, every known cause and UK cost bands — see our P0106 guide.