The ECU has run out of fuel trim on bank 2 trying to lean out an over-rich mixture — fuel is being delivered faster than the engine can burn it on that bank.
P0175 — also written PO175, P 0175, 0175 — is the OBD-II code for system too rich (bank 2). Same code, same fix: this page covers every spelling of it.
Bank 2 is getting too much fuel and not enough air, basically drowning the engine. It’s a classic headache on V6 and V8 engines where one side of the block is misbehaving.
P0175 is a fuel & air fault code, typically costing £60–£500 to put right in a UK garage.
What P0175 actually feels like to drive
- The car smells like a petrol station forecourt when you pull up at the lights.
- Rough idling that feels like a misfire, especially when the engine is warm.
- A noticeable drop in MPG—you'll be visiting the pumps a lot more than usual.
- Black soot build-up on the right-hand tailpipe (Bank 2).
- The engine 'hunts' up and down when you're sat in traffic.
- Occasional puff of dark smoke from the exhaust when you floor it onto a dual carriageway.
What causes P0175?
- Leaking or dribbling injector on bank 2
- Failed or contaminated MAF sensor
- Fuel pressure regulator stuck high
- Failed evap purge valve dumping vapour
- Stuck-closed upstream O2 sensor
UK vehicles that throw P0175 most often
- Jaguar XF 3.0 V6 (2008-2015) - Common injector seals
- Range Rover Sport 4.4 / 5.0 V8 - PCV valve issues
- BMW 335i / 535i (N54/N55 engines) - High-pressure fuel pump/injector failure
- Audi A6 3.2 FSI - Carbon buildup and injector spray patterns
- Vauxhall Insignia 2.8 V6 Turbo - Fuel pressure regulator faults
- Mercedes-Benz C320 / E320 V6 - MAF sensor degradation
How P0175 is fixed
- Injector balance / leak-down test
- Clean or replace the MAF
- Test rail pressure against spec
- Smoke-test intake for oil ingestion
The P0175 misdiagnosis that wastes money
I see lads constantly throwing a set of O2 sensors at this because the code description mentions them, but that's just shooting the messenger. More often than not on the older V6 Range Rovers or Jaguar XFs, it’s a tiny split in the air intake bellows or a dirty MAF sensor that’s over-reporting airflow. If you just swap the sensor without checking the fuel trims on a live data scanner, you’re just flushing the customer’s money down the drain. I've even seen 'cheap' aftermarket air filters causing turbulence that triggers a rich code on just one bank.
What a UK garage should charge for P0175
A proper diagnostic session with a smoke machine and live data will cost you £60 to £90 at a good independent. If it's just a dirty MAF, a clean is £40, but a new Bosch unit can be £120-£200. The big hit comes if it's an injector; on a Jag or BMW, you’re looking at £250-£400 per injector including labour. A fuel pressure regulator is usually a simpler £150 job. Avoid the main dealers unless you fancy paying £180 an hour just for them to plug it in.
P0175 repair cost in the UK
Most P0175 repairs land between £60–£500 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 P0175
If you take it to a garage, ask them to show you the 'long-term fuel trims' (LTFT) on their scan tool. If they just say 'the computer says sensor,' walk away. You want to insist on a fuel pressure leak-down test. If the pressure drops the second the engine is switched off, you’ve got a leaky injector bleeding fuel into the cylinder. Also, if you’re a DIYer, don’t buy a £20 MAF sensor from eBay; they’re absolute rubbish. Stick to Bosch, Denso, or NGK/NTK, or you’ll be chasing your tail for weeks.
Can you drive with P0175?
Yes short-term but expect poor MPG and fouled plugs — sustained rich running kills the cat.
Urgency: medium.