Bank 1 lean at idle only.
P2187 — also written P2187, P 2187, 2187 — is the OBD-II code for system too lean at idle (bank 1). Same code, same fix: this page covers every spelling of it.
This code means the engine is sucking in 'unmeasured' air that hasn't gone through the mass air meter, usually through a split hose or a bad PCV valve. We see this constantly on Vauxhall 1.4 turbos and the Peugeot-engined MINIs.
P2187 is a fuel & air fault code, typically costing £60–£400 to put right in a UK garage.
What P2187 actually feels like to drive
- The car idles like a bag of spanners at traffic lights but clears up once you're moving.
- The 'Check Engine' light pops on while stationary at a junction.
- A faint whistling or hissing noise coming from the engine bay at idle.
- The rev needle 'hunts' or bounces up and down when you're parked up.
- The car nearly stalls when you lift off the throttle to stop at a roundabout.
What causes P2187?
- Vacuum leak (most likely)
- Idle air control fault
- PCV valve
UK vehicles that throw P2187 most often
- Vauxhall Astra J/Corsa D 1.4 Turbo (A14NET) 2010-2015
- MINI Cooper/One 1.6 (N12/N16 engines) 2007-2013
- Volkswagen Golf/Scirocco 2.0 TSi (EA888) 2008-2014
- Audi A3/A4 1.8 & 2.0 TFSI 2007-2015
- Ford Focus 1.0 EcoBoost (early models) 2012-2015
- Mazda 3/6 2.0 MZR 2008-2013
How P2187 is fixed
- Smoke test
- PCV replacement
- Throttle service
The P2187 misdiagnosis that wastes money
I see so many folks waste money on an O2 sensor because the code reader says 'lean'. It's madness. That sensor is doing its job; it's telling you there’s too much air, not that it's broken. On the Minis and BMWs, people also throw a set of plugs at it. Nine times out of ten, it’s a split PCV diaphragm or a cracked breather hose tucked behind the intake manifold where you can't see it. The sensor is almost never the culprit.
What a UK garage should charge for P2187
A basic diagnostic plug-in is £50-£80. If it’s just a split vacuum pipe, you might get away with £60 for a fix. However, if that PCV/Oil Separator unit on a VAG or Vauxhall engine has failed, you’re looking at £150-£280 for a genuine or Bosch/Febi part plus an hour's labour. A main dealer will likely 'quote' you £500+ by insisting on a full throttle body service you probably don't need.
P2187 repair cost in the UK
Most P2187 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 P2187
Ask the garage if they have a smoke machine. Not a vape pen, a proper workshop smoke leak detector. If they say 'we'll just start swapping bits,' walk away. A 10-minute smoke test (usually about £40) will find a vacuum leak that you'd spend hours looking for otherwise. Also, if you’ve got a Vauxhall or a MINI, check the oil filler cap is tight—if the seal is perished, it’ll draw air and trigger P2187 just as quick as a burst pipe.
Can you drive with P2187?
Drivable.
Urgency: medium.