Code Definition

P2291 — Injector Control Pressure Too Low - Engine Cranking

System: Powertrain  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About P2291

P2291 is a generic (obd-ii standard) powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P2291 is stored, the module has detected a signal or supply voltage lower than the expected operating range.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

Because P2291 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

On diesel engines that use an injection control pressure (ICP) system, particularly Ford Powerstroke HEUI engines, the injectors need a minimum oil pressure to fire, and the ECM raises that pressure during cranking by commanding the injection pressure regulator (IPR) valve. DTC P2291 sets when the ECM sees the actual injection control pressure stay below the minimum threshold needed to start while the engine is cranking. Without enough pressure the injectors cannot deliver fuel properly, so the most common symptom is extended cranking, a no start, or a start that quickly stalls, often worse wh...

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