Injector circuit Cylinder 3 on Renault 1.5/1.6/2.0 dCi — Delphi injectors fail electrically, plus wiring harness corrosion on vans.
Renault P0203 — Injector circuit Cylinder 3 on Renault 1.5/1.6/2.0 dCi — Delphi injectors fail electrically, plus wiring harness corrosion on vans. Typical UK independent garage cost: £180–£720.
What actually causes P0203 on a Renault
Renault 1.5 dCi Delphi injectors have a known electrical failure mode where the internal solenoid winding goes open-circuit around 120k miles. On Trafic/Kangoo vans the cyl 3 injector wiring is routed near the bulkhead grommet which lets water in — corrosion on the spade terminals causes intermittent P0203. The newer DCM6.2 ECU on Megane IV is also less tolerant of cross-cylinder current draw, so even a slightly weak injector throws the code.
Renault engines that log P0203
- 1.5 dCi K9K (Clio, Megane, Captur, Kangoo, Trafic)
- 1.6 dCi R9M (Megane, Scenic, Kadjar, Trafic)
- 2.0 dCi M9R (Trafic, Master)
How we diagnose P0203 on a Renault
- CLIP / Renolink — read injector correction values
- Inspect cyl 3 connector for corrosion (very common on vans)
- Measure injector resistance from ECU connector pin (isolates wiring fault)
- Replace if electrical fault confirmed; code C2I value via CLIP
- Carry out fuel system priming and re-test
The common misdiagnosis to avoid
Renault dealers will often quote a complete injector set on a Kangoo van (£1,200+) when only cyl 3 has failed — Delphi reman individual injectors run £140–£190 with full warranty.
Renault P0203 repair cost in the UK
Expect £180–£720 including parts and labour at an independent garage. Main-dealer quotes on Renault 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
Always strip and replace the bulkhead grommet on Kangoo/Trafic vans showing injector connector corrosion — otherwise the new wiring will rot through within a year of UK winter salt.
Codes usually seen alongside P0203 on Renault
- P0201
- P0202
- P0204
- P1485
Symptoms drivers report with P0203
- Engine drops into limp mode at motorway speeds, then resets after a restart
- Slight knock or 'diesel knock' specifically when cold
- Loss of power above 2,500 RPM only
- Slightly elevated fuel consumption (1–3 MPG drop)
- Code returns within 100 miles of clearing
Repairs that clear P0203
- Injector replacement
For the generic, all-makes explanation of this code — meaning, every known cause and UK cost bands — see our P0203 guide.
Reading P0203 on a Renault properly
A generic reader will show P0203 and nothing else. What matters is the freeze-frame data stored with it — engine speed, load, coolant temperature and fuel trims at the moment the fault was logged — plus whether any other module on the Renault has logged something at the same time. Codes rarely arrive alone, and the order they were stored in usually points at which one is the cause and which are the consequences.
Clearing P0203 without fixing it
Erasing the code resets the Renault's readiness monitors as well as the light. The fault returns on the next drive cycle if the cause is still there, and in the meantime the incomplete monitors can stop the car passing an emissions check. After a genuine repair, the car is driven until the relevant monitor completes before it is handed back.
Bob's Mechanical Repairs is an independent garage in Birnam, Dunkeld, Perthshire, with 32 years of Bob's experience on the tools. If P0203 is showing on your Renault, bring any scan results with you — we will read the live data ourselves, confirm which cause it actually is, and price the repair before any work starts.