P0203 serious

Injector Circuit Malfunction - Cylinder 3

What does P0203 mean?

The P0203 code means the vehicle's onboard diagnostic system has detected: Injector Circuit Malfunction - Cylinder 3. This is a serious severity code.

Common Symptoms

  • Check Engine Light on
  • Misfire on cylinder 3
  • Rough idle
  • Power loss
  • Fuel smell

Probable Causes (Ranked by Likelihood)

  • Wiring fault at cylinder 3 injector Very High
  • Failed cylinder 3 injector High
  • PCM driver fault for cylinder 3 Moderate

Step-by-Step Diagnostic Procedure

  1. NOID light test on cylinder 3 injector.

  2. Resistance test on cylinder 3 injector.

  3. Wiring continuity check.

  4. Injector balance test.

Frequently Asked Questions

Does a cylinder 3 injector fault always cause a misfire?

An open injector circuit (no fuel) will cause a misfire. A shorted circuit may cause intermittent issues or just the circuit code without a misfire, depending on whether the injector still opens partially.

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