Diesel Trouble Codes

P0262 — Cylinder 1 Injector Circuit High (7.3 Power Stroke)

P0262 is a per-cylinder injector circuit fault on the 7.3L Power Stroke HEUI system. The PCM/IDM has detected abnormally high voltage/current in the cylinder 1…

Updated September 2, 2026

What it means

The engine control module has detected an abnormally high voltage or current in the injector circuit for cylinder 1. On the 7.3L Power Stroke this is a HEUI, IDM-driven injector circuit fault, not a common-rail pressure issue.1

Most likely causes

  1. Open or high-resistance in the cylinder 1 injector control circuit (IDM output to injector). — The IDM drives the HEUI injectors; an open, corroded, or oil-soaked connection raises circuit voltage/current seen by the PCM/IDM. Per-cylinder injector circuit faults are P0261/P0262 for cylinder 1 on this platform.12
  2. Under-Valve-Cover Harness (UVCH) failure at cylinder 1. — The UVCH connectors and pigtails under the valve cover are a known failure point on 7.3L Power Stroke, often oil-soaked or chafed, causing injector and glow-plug circuit codes.2
  3. Faulty or damaged cylinder 1 injector solenoid/electrical connector. — A failed injector electrical element or damaged connector can present as high circuit voltage/current to the IDM/PCM.1
  4. Injector Driver Module (IDM) output fault for cylinder 1. — The IDM is a separate module on the driver-side fender that drives the injectors; an internal output fault can set a per-cylinder high circuit code. IDM/output-circuit faults are P1660, P1662, P1663 on this platform.2
  5. PCM detection/wiring issue between PCM and IDM for cylinder 1 control. — Wiring, connectors, or PCM input processing can cause the PCM to read abnormally high voltage/current on the cylinder 1 injector circuit.1

How to diagnose

  1. Verify code and freeze-frame; confirm P0262 is present and not accompanied by ICP/IPR or IDM codes.
  2. Inspect IDM power/ground and main engine harness connectors for corrosion, oil contamination, or loose pins.
  3. Check UVCH at cylinder 1 for oil intrusion, chafing, or damaged pins; inspect injector connector and pigtail under valve cover.
  4. Perform electrical tests of the cylinder 1 injector control circuit resistance/continuity from IDM connector to injector, comparing to other cylinders.
  5. Inspect IDM and its connectors for moisture/oil; verify IDM power/ground integrity.
  6. If circuit tests normal, evaluate IDM output behavior and PCM inputs for cylinder 1; compare to known-good values.
  7. Clear codes and retest after repairs to confirm circuit returns to normal.
  8. Note: Do not describe this engine as common-rail; 7.3L Power Stroke uses HEUI with HPOP/ICP/IPR, no rail pressure sensor.

Parts and tools you may need

Rough cost and difficulty

Parts cost varies by component (UVCH, injector, IDM). Labor is higher if valve cover removal is required. Diagnosis should confirm the electrical fault before replacing parts.

When to see a pro

If the fault persists after UVCH and wiring checks, or if IDM/PCM involvement is suspected, have a diesel technician with 7.3L HEUI experience perform IDM output testing and PCM evaluation. Do not attempt high-pressure oil or injector removal without proper training and safety precautions.

Sources

  1. Curated DTC seed — 7.3 Power Stroke (curated) ↩︎ ↩︎ ↩︎ ↩︎

  2. Curated DTC seed — 7.3 Power Stroke (curated) ↩︎ ↩︎ ↩︎