Fuel and air

P2291 — Injector Control Pressure Too Low During Cranking

Severity: medium Drive with care, to a shop

What P2291 means

While the engine cranks, the ECM compares the ICP sensor reading with the minimum pressure needed to fire the injectors. The high-pressure oil pump (HPOP) normally builds this pressure to actuate HEUI-style injectors. If pressure stays too low, the injectors will not fire and the engine will not start. This code is a classic on Ford 6.0L and 6.4L Power Stroke diesels.

Symptoms

  • Long cranking with no start
  • ICP reads low on a scan tool
  • Check Engine light on
  • Possible rough running or misfire
  • Possible increased fuel consumption

Possible causes

  1. Failed high-pressure oil pump (HPOP)
  2. Sticking injectors (stiction)
  3. Faulty ICP sensor
  4. Low engine oil level
  5. Leaks in the high-pressure oil circuit (valves, seals, lines)
  6. Fuel pressure regulator or fuel supply problem
  7. Damaged ICP sensor wiring or connector

How to diagnose

  1. Check oil level and condition
  2. Scan for codes and watch ICP data during cranking
  3. Inspect the ICP sensor connector and wiring, test power and ground
  4. Compare the ICP reading with actual pressure measured mechanically
  5. Check fuel pressure and the condition of the fuel filter
  6. Inspect the high-pressure oil system for leaks at seals and lines
  7. Test for sticking injectors and run a cylinder balance test

Common fixes

  • Top off or change oil and filter
  • Replace the ICP sensor or repair the wiring
  • Replace leaking seals, lines or valves in the high-pressure oil circuit
  • Replace the HPOP
  • Replace or service sticking injectors

Questions and answers

What does P2291 mean?

Injector control pressure is too low while the engine is cranking. The injectors then cannot fire, so the engine will not start or starts only with difficulty.

Can I drive with P2291?

If the engine runs, only briefly and carefully. It can stall without warning, so have it repaired soon.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.