Diesel Trouble Codes

P0205 — Injector Circuit / Open (5.9 Cummins Common Rail)

The ECM has detected an electrical fault in the injector circuit for cylinder 5 on a 5.9L Cummins Common Rail 2003-2007.

Updated September 2, 2026

What it means

The engine control module has detected an electrical fault in the injector circuit for cylinder 5. On this platform injectors are Bosch common-rail solenoid type and electrical faults show as P0201-P0206; contribution/balance issues show as P0263-family.123

Most likely causes

  1. Open or high resistance in cylinder 5 injector harness/connectors — Inspect the injector connector and engine harness for corrosion, backed-out pins, chafing or oil intrusion at the valve cover pass-through. Check continuity from ECM to injector and look for intermittent opens that set P0205.123
  2. Failed cylinder 5 injector solenoid/electrical coil — A failed injector solenoid or internal open in the injector coil will set an injector circuit/open code for that cylinder. Compare resistance to spec and to other cylinders.123
  3. ECM driver fault for cylinder 5 injector — Internal ECM injector driver failure can cause a circuit/open detection for a single cylinder. Verify wiring first; if wiring and injector test good, suspect ECM.123

How to diagnose

  1. Verify code P0205 is present and check for additional injector codes P0201-P0206.
  2. Inspect cylinder 5 injector connector, terminals and harness for damage, corrosion or oil contamination; repair as needed.
  3. Measure injector solenoid resistance at the injector connector and compare to other cylinders; look for open or out-of-spec reading.
  4. Perform a continuity and isolation check of the injector wiring from ECM connector to injector connector; wiggle test harness while monitoring.
  5. If wiring and injector test good, evaluate ECM injector driver output with a scope or scan tool bi-directional test; consider ECM if fault persists.

Parts and tools you may need

Rough cost and difficulty

Diagnostic labor varies; injector harness repair is typically lower cost than injector or ECM replacement. Actual parts cost depends on injector condition and whether ECM service is required.

When to see a pro

If wiring tests good and injector resistance is normal but P0205 returns, have the ECM evaluated by a qualified diesel technician. Do not attempt high-pressure fuel system service. If drivability is affected, stop driving and seek professional diagnosis.

Sources

  1. Curated DTC seed — 5.9 Cummins Common Rail (curated) ↩︎ ↩︎ ↩︎ ↩︎

  2. Curated DTC seed — 5.9 Cummins Common Rail (curated) ↩︎ ↩︎ ↩︎ ↩︎

  3. Curated DTC seed — 5.9 Cummins Common Rail (curated) ↩︎ ↩︎ ↩︎ ↩︎