Low signal at cyl 1 injector.
P0261 — also written PO261, P 0261, 0261 — is the OBD-II code for cylinder 1 injector circuit low. Same code, same fix: this page covers every spelling of it.
This code means the ECU has spotted a weak electrical signal going to the first injector, usually because a wire has snapped or the solenoid inside the injector has given up the ghost. It's a proper nuisance on the common 1.6 and 2.0 diesel engines we see across the UK.
P0261 is a fuel & air fault code, typically costing £120–£600 to put right in a UK garage.
What P0261 actually feels like to drive
- The car feels like it’s running on three cylinders, shaking like a wet dog at traffic lights.
- Engine Management Light (EML) is on, often accompanied by the 'Anti-pollution system fault' message on French cars.
- Severe 'pinken' or knocking sound when you try to accelerate hard.
- She'll start up okay-ish when stone cold, but as soon as the heat gets into the loom, she starts missing.
- Dreadful fuel economy and a smell of unburnt diesel or petrol from the tailpipe.
What causes P0261?
- Wiring open
- Failed injector
UK vehicles that throw P0261 most often
- Volkswagen Golf/Passat 2.0 TDi (BKD/CFFB) 2005-2015
- Ford Focus/Fiesta 1.6 TDCi (DV6) 2008-2014
- Vauxhall Insignia 2.0 CDTi (A20DTH) 2008-2017
- Peugeot 308/508 1.6 BlueHDi 2014-2019
- Audi A3/A4 2.0 TDi (Common Rail models) 2008-2016
- Land Rover Freelander 2 2.2 SD4 2010-2014
How P0261 is fixed
- Wiring repair
- Injector swap
The P0261 misdiagnosis that wastes money
I see it constantly: a DIYer or a 'parts cannon' shop sees 'Cylinder 1' and instantly buys a new injector. They slap a reconditioned Bosch unit in, only for the car to still misfire exactly the same way. In my experience, especially on the VWs, the actual culprit is often the wiring loom where it passes through the cylinder head or a corroded pin in the ECU connector. Changing the injector first is a £200 gamble you'll likely lose if you haven't checked for a pulse with a noid light or a scope first.
What a UK garage should charge for P0261
An independent like mine will charge about £60 to £90 for the initial diagnostic scan and scope test. If it’s just a broken wire, you’re looking at £120-£150 all in. If the injector is shot, a brand new Bosch or Delphi unit is generally £220 to £350 plus an hour's labour to fit and code it. A main dealer will likely quote you north of £600 once they've added their 'premium' hourly rate and 20% VAT on top of everything.
P0261 repair cost in the UK
Most P0261 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 P0261
If a garage tells you that you need a new injector, ask them flat out: "Have you performed a resistance test on the injector and a load test on the wiring?" If they look at you blankly, take your car elsewhere. On the 1.6 TDCi Fords/Peugeots, the wiring harness often rubs through against the engine lifting eye or the plastic cover. Insist they do a 'wiggle test' on the loom while the engine is running. It might just be a 20-minute wire solder job rather than a £400 injector replacement.
Can you drive with P0261?
Avoid driving.
Urgency: high.