Error code

OBD2 P0203

OBD2P0203
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.

What it means

Injector Circuit/Open - Cylinder 3.

Severity

highDrive cautiously and seek repair immediately to avoid further engine damage.

Summary

P0203 indicates an issue with the fuel injector circuit for cylinder 3 in your vehicle's engine.

Symptoms

  • Engine misfire
  • Engine stalls
  • Cranking but not starting

Common Causes

  • Failed fuel injector
  • Faulty wiring or connector in the injector circuit
  • Problem with the Powertrain Control Module (PCM)

Diagnosis

  1. Visually inspect the fuel injectors and connections for any obvious issues.
  2. Use a scan tool to check for misfire codes (P0301-P0308) and monitor cylinder misfires using Mode $06.
  3. Test the injector circuit with a noid light by disconnecting the injector and inserting the light into the connector. The light should flash when cranking the engine.
  4. Check power to the injector using a test light connected to ground and the B+ pin on the injector connector.
  5. Verify that the PCM is properly grounding the injector using another test light attached to battery power and the ground side of the injector connector.
  6. Use a digital multimeter to check continuity between the PCM and injector, as well as measure resistance in the injector itself.

Fixes

  • Replace faulty fuel injector or repair wiring/connectors

FAQ

What should I do if my car has a P0203 code?

You should perform the diagnostic steps outlined above to identify and fix the issue. If you're not comfortable doing this yourself, take your vehicle to a professional mechanic.

View source

Not affiliated with OBD2. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.

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