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.

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

1. CLIP / Renolink — read injector correction values
2. Inspect cyl 3 connector for corrosion (very common on vans)
3. Measure injector resistance from ECU connector pin (isolates wiring fault)
4. Replace if electrical fault confirmed; code C2I value via CLIP
5. 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.