Diesel Trouble Codes

P0201 — Injector Circuit/Open - Cylinder 1 (6.4 Power Stroke)

Diagnostic reference for 6.4L Power Stroke 2008-2010. Common-rail piezo injectors controlled via FICM; no HEUI/ICP/IPR. Diagnose electrical circuit fault for…

Updated September 2, 2026

What it means

The engine control module has detected an electrical fault in the fuel injector circuit for cylinder number one. On the 6.4L Power Stroke this is a common-rail piezo injector system with FICM control; no HEUI/ICP/IPR apply.1

Most likely causes

  1. Open or high-resistance in injector harness/connectors at cylinder 1 — Inspect wiring, pins, and connector at injector 1 for corrosion, chafing, or loose terminals. Check continuity from FICM to injector 1. Typical on this platform: 6.4L Power Stroke 2008-2010 common rail piezo with FICM; no HEUI/ICP/IPR.1
  2. Failed injector solenoid/piezo element on cylinder 1 — Internal electrical open in injector 1. Compare circuit resistance to other cylinders; abnormal reading supports injector fault. Generic definition: ECM detected electrical fault in fuel injector circuit for cylinder number one.1
  3. FICM output driver fault for cylinder 1 — FICM controls piezo injectors on 6.4L. A driver fault can set P0201 for one cylinder while others remain normal. Typical on this platform: 6.4L Power Stroke 2008-2010 uses common rail piezo injectors controlled via FICM.2
  4. PCM/FICM power/ground issue affecting cylinder 1 driver — Low voltage or poor ground to FICM can cause intermittent circuit/open codes. Verify FICM power and ground circuits and related fuses/relays. Platform uses FICM for injector control.1

How to diagnose

  1. Verify code and freeze frame; confirm P0201 is present and not accompanied by contribution/balance codes.
  2. Visually inspect injector 1 connector and harness for damage, oil intrusion, or corrosion.
  3. Measure injector circuit resistance/continuity from FICM connector to injector 1 and compare to other cylinders.
  4. Check FICM power and ground supplies and related fuses/relays.
  5. Swap injector electrical connector with adjacent cylinder to see if code follows wiring vs injector.
  6. Review live data for injector circuit status and FICM voltage during key-on/engine-off and idle.
  7. If circuit tests normal, evaluate FICM performance; P0611 indicates FICM performance issues on this platform.

Parts and tools you may need

Rough cost and difficulty

Parts and labor vary by region and shop. High-pressure fuel system work requires specialized tools and safety precautions.

When to see a pro

If diagnosis points to FICM failure, high-pressure fuel system access, or internal injector failure, have a qualified diesel technician perform testing and repair. Do not service high-pressure fuel lines or components without proper training and safety equipment.

Sources

  1. Curated DTC seed — 6.4 Power Stroke (curated) ↩︎ ↩︎ ↩︎ ↩︎

  2. Curated DTC seed — 6.4 Power Stroke (curated) ↩︎