Diesel Trouble Codes

P0093 — Fuel System Leak Detected - Large Leak — 6.7 Powerstroke

Diagnostic reference for 6.7 Powerstroke (2011–present) P0093. Focus on high-pressure fuel leak detection and safe diagnostic steps without performing…

Updated October 15, 2026

What it means

P0093 means the PCM sees a rail-pressure drop it can only account for as a large high-pressure fuel leak. On the 6.7L Power Stroke treat it as a real high-pressure fuel leak (injector, line or fitting, pump) until a sensor fault is proven; high-pressure fuel can penetrate skin.1

Most likely causes

  1. High-pressure injector leak or failure — Internal or external leak at an injector causes rapid rail-pressure loss under load. Typical on this platform as a real high-pressure fuel leak.1
  2. High-pressure fuel line or fitting leak — Cracked line, loose or damaged fitting on the high-pressure side leads to large rail-pressure drop.1
  3. High-pressure fuel pump failure or internal bypass — Pump cannot maintain rail pressure, mimicking a large leak.1
  4. Rail pressure sensor or wiring fault — Erroneous low rail-pressure signal can set P0093. On the 6.7L Power Stroke treat as a real leak until a sensor fault is proven.1

How to diagnose

  1. Verify freeze-frame conditions and repeat the fault under controlled load. Record rail-pressure actual vs desired during a snap-throttle event.
  2. Inspect high-pressure fuel system externally for signs of diesel spray or wetness. NHTSA reports describe fuel system failures with diesel fuel sprayed over the engine and fire risk.
  3. Check for accompanying codes that point to sensor or electrical issues (e.g., MAP/BARO circuit low). MAP/BARO sensor signal below valid range affects boost control.
  4. Perform a controlled rail-pressure leak-down test using a scan tool; monitor pressure decay after engine stop. A rapid drop supports a large leak.
  5. Inspect intake and air-filter condition to rule out secondary effects. Intake restriction or unmetered air leak is detected upstream of the sensor.
  6. If underboost is present, inspect charge-air system. Boost pressure below minimum expected can be caused by charge-air-cooler boot leaks, VGT vanes stuck open, sticking turbo actuator, or a restricted air filter.

Common mistake to avoid

Replacing only the high-pressure pump after a CP4 failure. A failed CP4 can send metal through the injectors, lines and tank; check the fuel and filters for debris first, because a contaminated system needs more than a pump. Source: DieselHub — common 6.7 Power Stroke problems.

Parts and tools you may need

Tools you’ll need

Rough cost and difficulty

Likely repairPartsShop laborWho usually does it
Fuel supply or return line repair$30–$2000.5–2 hrsDIY with tools and a manual
Fuel rail pressure sensor$100–$4001–3 hrsDIY with tools and a manual
Fuel injector (each)$400–$8002–4 hrsShop
CP4.2 high-pressure fuel pump$1,000–$2,0004–8 hrsShop

Typical US independent-shop figures; labor runs about $120–$180 per hour (dealers charge more). Confirm the diagnosis before buying parts.

When to see a pro

High-pressure diesel fuel can penetrate skin and cause injury. Do not open or pressurize high-pressure fuel components. Have a qualified diesel technician perform high-pressure fuel system testing and repairs. NHTSA reports include engine fires after heavy fuel smell/odor.

Check for recalls

Recalls are tied to your truck’s VIN, so check yours directly: enter the VIN at NHTSA’s recall lookup. Open safety recalls are repaired free at a dealer.

Sources

  1. Curated DTC seed — 6.7 Powerstroke (curated) ↩︎ ↩︎ ↩︎ ↩︎ ↩︎

Repair videos: P0093 on the 6.7 Power Stroke

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

How to Fix P0093 on Ford 6.7 Diesels — Shop Talk · 31K views

Diag Summary - Ford 6.7L Powerstroke Intermittent P0093 - Internal Large Leak Only At 28,000psi — The Keeney Garage · 2K views

How to Diagnose if your CP4 Fuel Pump is Failing — XDP · 225K views