P0203 on BMW: Causes, Symptoms and Fix Cost
Quick Answer
Safe to drive (short-term)
P0203 on a BMW tells you the engine computer found an electrical fault in the circuit of the cylinder 3 injector: open, shorted or outside its resistance limits. On a four-cylinder it is an inner cylinder next to cylinder 4, and on three-cylinder engines such as Ford's 1.0 EcoBoost it is the last cylinder in the row. Workshop wiring repairs cost about 65-220 EUR; a petrol injector fitted about 100-310 EUR.
- Severity
- Moderate · Fuel System
- Typical repair cost, all makes
- €5-€650
Connect a standard OBD2 adapter (Bluetooth LE on iPhone) to your BMW and Skanyx tells you what P0203 means on that engine, whether it is safe to keep driving, and what the fix should cost. Free on iPhone and Android.
Get Skanyx freeWhat does P0203 mean on a BMW?
The Quick Answer above is the generic definition. What follows is the model-specific detail for the BMW models that log P0203.
BMW 3 Series
2005-2024
Direct-injection petrol engines (N20, N55, B48) use solenoid or piezo injectors with connectors that can corrode or work loose. On N47/B47 diesels the common-rail injectors are costly and need injector coding after replacement, which requires Carly, ISTA, or a workshop. Skanyx reads the generic circuit code and any misfire codes, but not the per-injector adaptation data.
What causes P0203 on a BMW?
Beyond the generic causes listed on the main P0203 page, these are the patterns noted for BMW models:
Corroded or loose injector connector on N20/B48 petrol
: BMW 3 Series
Diesel common-rail injector failure requiring coding on N47/B47
: BMW 3 Series
How to diagnose P0203 on a BMW with OBD2
- Read P0203 and the freeze frame with Skanyx. Note any P0303 (cylinder 3 misfire), P0267 or P0268 (cylinder 3 injector circuit low or high) and other injector codes stored at the same time
- Work out where cylinder 3 is. On a four-cylinder engine it is the third from the pulley end, next to cylinder 4 at the gearbox end. On a three-cylinder engine it is the last cylinder, at the gearbox end. On V6 and V8 engines cylinder 3 is on bank 1 whichever numbering the maker uses
- Inspect the cylinder 3 injector connector and the branch of harness feeding it. Look for a cracked latch, corrosion in the pins and insulation worn through where the loom is clipped to the engine
- If P0203 was stored together with another injector code, check the shared supply fuse, relay and ground first. Two injectors failing at the same moment is much less likely than a fault in something they share
- Measure the injector coil at its pins with the ignition off, then repeat from the ECU pin for injector 3 to include the harness. Use the specification for your engine type
- Swap injector 3 with a neighbour, cylinder 2 or 4 (cylinder 2 on a three-cylinder), clear the code and drive. If the code moves with the injector, replace it; if P0203 stays, repair the wiring or check the ECU driver
- When a direct-injection injector is removed, fit new PTFE combustion seals before refitting. On common-rail diesels the injector correction codes must match each cylinder, which needs a brand tool or a workshop
How much does P0203 cost to fix on a BMW? (EUR)
Estimated repair costs for P0203 in EUR, compiled across makes. Expect BMW parts and labour towards the upper end of each range.
| Repair | Parts Cost | Labor Cost | Total Estimate | DIY Difficulty |
|---|---|---|---|---|
| DIY repair of the cylinder 3 connector or wiring | €5–€30 | €0–€0 | €5–€30 | Moderate |
| Cylinder 3 circuit traced and repaired at a workshop | €5–€40 | €60–€180 | €65–€220 | Professional |
| Cylinder 3 petrol injector replaced at a workshop | €40–€150 | €60–€160 | €100–€310 | Moderate |
| Cylinder 3 common-rail diesel injector replaced at a workshop | €150–€400 | €100–€250 | €250–€650 | Professional |
Prices estimated as of October 2026. Costs vary by region, vehicle, and shop.
Codes related to P0203
These codes are often seen alongside P0203 or point to related issues, on any make:
Looking for the full P0203 reference (all makes, full diagnosis flow, complete repair cost matrix)? See the main P0203 guide