Cylinder 4 injector circuit fault.
P0204 — also written PO2O4, P 0204, 0204 — is the OBD-II code for injector circuit — cylinder 4. Same code, same fix: this page covers every spelling of it.
Cylinder 4's injector has stopped talking to the brain, usually because the internal coil has fried or the wiring loom has chafed through on the airbox. We see this constantly on the 1.6 diesel Fords and PSA vans.
P0204 is a fuel & air fault code, typically costing £120–£600 to put right in a UK garage.
What P0204 actually feels like to drive
- Engine feels like it's 'shaking itself to bits' at traffic lights.
- Total loss of power when trying to merge onto the A9 or M8.
- The car 'kangaroos' violently under load but might idle halfway decent.
- Audible 'ticking' or 'clacking' sound coming from the top of the block.
- Sudden 'Limp Home Mode' with the curly glow plug or engine light glowing.
What causes P0204?
- Failed injector
- Wiring
UK vehicles that throw P0204 most often
- Ford Focus 1.6 TDCi (DV6) 2011-2015
- Vauxhall Vivaro 1.9 CDTi (M9R) 2006-2014
- Peugeot Partner 1.6 HDi 2008-2018
- Volkswagen Golf Mk6 1.6 TDI (CAYC engine) 2009-2013
- Vauxhall Astra J 1.7 CDTi 2009-2014
- Citroen Berlingo 1.6 BlueHDi 2015-onwards
How P0204 is fixed
- Injector replacement
The P0204 misdiagnosis that wastes money
I see too many lads jump straight to the ECU because they 'heard' these units fail, but 9 times out of 10, it’s a simple mechanical failure of the injector solenoid or the loom itself. Don't be the bloke who spends £500 on a refurbished ECU only to find the same misfire because a £20 Euro Car Parts wiring pig-tail was actually the culprit. On the 1.6 TDCi units, we often see people replacing all four injectors when only cylinder 4 has the electrical break—it’s a waste of the customer's brass.
What a UK garage should charge for P0204
For a basic diagnostic plug-in, expect to pay £50 to £80 at a good independent. If it’s just the wiring connector, I’d charge you £120 all-in. However, if the injector is truly knackered, a new Bosch unit is about £220 plus an hour's labour (£70-£100). If you go to a main dealer, you’re looking at £500-£600 easily for the same job. Always factor in the 'coding'—we have to tell the ECU the new injector's calibration code or it’ll run like a bag of spanners.
P0204 repair cost in the UK
Most P0204 repairs land between £120–£600 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 P0204
If a garage tells you that you need a new engine or a 'full fuel system flush' for a P0204, get your keys and run. Insist they do a 'noid light' test or a resistance check on the injector itself first. A healthy solenoid should show a specific Ohm reading (usually 12-14 ohms for standard, much less for Piezo). If the injector is dead, ask if they’re fitting a Bosch or Delphi unit—don't let them fit a 'no-name' white box special from eBay, or you'll be back in my workshop in three months with the same light on your dash.
Can you drive with P0204?
Avoid driving.
Urgency: high.