Diesel Trouble Codes

P0263 — Cylinder 1 Contribution/Balance Fault (6.7 Cummins (SCR / DEF))

Diagnostic reference for 6.7L Cummins SCR/DEF 2013–present. If sources do not support a point, leave it out. Describe how to DIAGNOSE, not step-by-step repair…

Updated September 2, 2026

What it means

The PCM detects that cylinder 1 output deviates from the others (Pxx6x family covers cylinders 1-8).1

Most likely causes

  1. Cylinder 1 injector performance / balance issue — Solenoid injector for cylinder 1 delivering uneven fuel quantity vs other cylinders; PCM flags contribution/balance fault. Typical on this platform: 6.7L Cummins 2013–present (SCR/DEF).1
  2. Injector electrical circuit fault for cylinder 1 — Engine control module detects electrical fault in fuel injector circuit for cylinder number one.2

How to diagnose

  1. Verify code P0263 present and check for accompanying injector circuit codes such as P0201 for cylinder 1.
  2. Review freeze-frame data for engine speed, load, rail pressure, and fuel temperature at time of set.
  3. Perform cylinder contribution/balance test using scan tool to confirm cylinder 1 deviation.
  4. Inspect injector electrical connector and harness for damage, corrosion, or loose pins at cylinder 1.
  5. Check injector driver circuit integrity and ECM injector control signals for cylinder 1.
  6. Compare rail pressure actual vs desired during idle and load; note platform uses Bosch CP3 for 2013–2018 and 2021+, CP4.2 for 2019–2020 only.
  7. Assess low-pressure supply from factory in-tank electric supply pump / fuel module for adequate volume and pressure.
  8. Inspect common-rail solenoid injectors condition; P0201–P0206, P0263-family apply to this platform.

Parts and tools you may need

Rough cost and difficulty

Costs vary by model year, labor, and parts source. Get a written estimate before work begins.

When to see a pro

If diagnosis indicates internal injector failure, high-pressure fuel system concern, or ECM driver fault, have a qualified diesel technician evaluate. Do not attempt step-by-step repair of high-pressure fuel components.

Sources

  1. Curated DTC seed — 6.7 Cummins (SCR / DEF) (curated) ↩︎ ↩︎

  2. Curated DTC seed — 6.7 Cummins (SCR / DEF) (curated) ↩︎

Watch a repair

Third-party videos, not ours — for illustration. Confirm anything against the factory service information for your truck.

Diagnosing Cylinder Contribution Codes (6.7 Powerstroke) — John Kangas · 29K views

How to Replace and Program a Ford 6.7L Power Stroke® Diesel Fuel Injector — Motorcraft Parts · 155K views