TORKO

P0203 Cylinder 3 injector A circuit

What P0203 means

The engine computer has detected an electrical problem in the circuit that operates the fuel injector for cylinder 3: an open circuit, short or implausible current. If the injector is not being switched, cylinder 3 gets no fuel and misfires.

P0203 is a generic SAE J2012 code: it means the same on every make. The exact cause still depends on the car, so read the freeze-frame data before replacing parts.

At a glance

Severity
Medium
Typical repair cost
80–450 €
Workshop time
0.5–3.5 h
Repair difficulty
Medium
DIY possible
Yes
Check engine light
Yes
Affects emissions test
Yes

Parts and labour at an independent workshop in Europe. Main dealers charge more; the cause decides the bill, not the code.

Symptoms

Common causes

  1. Loose, unplugged or corroded connector on the cylinder 3 injector
  2. Damaged wiring between the injector and the engine computer (chafing, heat, rodents)
  3. Injector coil open or shorted internally
  4. Engine control unit injector driver fault (rare)

Can I keep driving with P0203?

You can drive gently to a workshop, but have it checked within one to two weeks. If cylinder 3 is misfiring or the check engine light flashes, avoid driving: unburned fuel can damage the catalytic converter.

What to check first

  1. Inspect the cylinder 3 injector connector and wiring for damage and corrosion; clean and reseat the connector.
  2. Measure the cylinder 3 injector coil resistance and compare it with the other injectors and the specification.
  3. Check for supply voltage at the injector and a switching control signal with a test light while cranking.
  4. Swap the injector with another cylinder if possible: if the fault follows the injector, replace it; if not, trace the wiring.

Related codes

Data: TORKO fault-code catalogue, built on OBDex (CC0-1.0) and reviewed against workshop practice. Informational only — it does not replace a diagnosis by a mechanic.
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