Technical Description of OBD-II Trouble Code
The engine cranking is causing the injector control pressure to be too low.
Meaning of P2291
P2291 is a generic powertrain code that applies to many OBD-II vehicles (1996-newer), including Ford, Range Rover, BMW, Peugeot, and others. The exact repair steps may vary depending on the year, make, model, and powertrain configuration.
When a P2291 code is stored, it means that the powertrain control module (PCM) has detected insufficient oil pressure to control the high-pressure fuel injection system while the engine is cranking.
This code is primarily used in high-pressure diesel injection systems but can also be used in vehicles with gasoline engines. The PCM monitors high-pressure injection using one or more fuel pressure sensors. Excessive injector control pressure can indicate a serious malfunction in the engine lubrication and/or timing mechanisms, which are crucial for the diesel high-pressure injection system. The stored code P2291 can be attributed to either a mechanical or electrical condition.
If the PCM detects insufficient injector oil pressure, it will store a code P2291 and illuminate the malfunction indicator lamp (MIL). Multiple ignition cycles with a failure may be required for MIL illumination.
Here is an example of a typical injection control pressure ICP sensor:
Severity of this DTC
Conditions contributing to a stored code P2291 can result in catastrophic engine damage. Therefore, this code should be considered severe.
Symptoms of the Code
Symptoms of a P2291 trouble code may include:
Common Causes of the Code
Causes for this code may include:
Troubleshooting Steps for P2291
Start by checking the engine oil level and ensuring that no oil pressure or oil level lamps are illuminated. If everything is in order, perform a manual oil pressure test. Engine timing components are affected by engine oil pressure, and low oil pressure can adversely affect injection timing.
To accurately diagnose a code P2291, you will need a diagnostic scanner, a digital volt/ohmmeter (DVOM), and reliable vehicle information. It may be helpful to search for technical service bulletins (TSB) that match the stored code, vehicle information, and symptoms. These bulletins can provide a quick solution to your diagnosis.
Connect the scanner to the vehicle diagnostic port and retrieve all stored codes and freeze frame data. Write down the information in case the code is intermittent. Clear the codes and test drive the vehicle until either the code is restored or the PCM enters readiness mode.
If the PCM enters readiness mode, diagnosing the code may be more difficult because it is intermittent. The condition that caused the P2291 code to be stored may need to worsen before an accurate diagnosis can be made. If the code is restored, continue with the diagnosis.
Use your source of vehicle information to obtain connector face views, connector pinout charts, component locator charts, wiring diagrams, and diagnostic flow charts specific to the code and vehicle in question.
Inspect the related wiring and connectors visually. Repair or replace any wiring that is cut, burned, or damaged.
Use the DVOM to test voltage and ground circuits at the injection system pressure sensor/s. If no voltage is detected, check the system fuses and replace any blown or defective fuses.
If voltage is detected, test the corresponding circuit at the PCM connector. If no voltage is detected there, suspect an open circuit between the sensor and the PCM. If voltage is present, suspect a defective PCM or PCM programming error.
Test the injection pressure sensor with the DVOM. If it does not meet the manufacturer’s specifications, consider it defective.
