P2293

DTC P2293

Description
The common rail fuel system is comprised of two fuel pressure sections: a suction side between the fuel tank and the fuel supply pump and a high-pressure side between the fuel supply pump and the fuel injectors. Fuel is drawn from the fuel tank via a feed pump and then pumped into the fuel rail by two plungers, all of which are internal to the fuel supply pump. This high pressure is regulated by the engine control module (ECM) using the fuel rail pressure (FRP) regulator dependant upon values from the FRP sensor attached to the fuel rail.

Under normal conditions, the fuel pressure will oscillate slightly due to the characteristics of the two-plunger fuel supply pump system. However, if one of the plungers is stuck or the cylinder it rides in is worn out, fuel pressure oscillations will be much higher. If the ECM detects that the fuel pressure is oscillating too much continuously for a certain length of time, this DTC will set. (Pressure Oscillation DTC)

In case of fuel rail overpressure, a pressure limiter valve threaded into the fuel rail will open to release overpressure and return fuel back to the fuel tank. If the ECM detects that the fuel pressure went high for a lengthy period of time this DTC will also set. (High Fuel Pressure DTC)

Condition for Running the DTC
Pressure Oscillation DTC
- DTCs P0016, P0089, P0091, P0092, P0192, P0193, P0201, P0202, P0203, P0204, P0261, P0264, P0267, P0270, P0300, P0301, P0302, P0303, P0304, P0335, P0336, P0602, P0642, P0643, P1293, P2146, P2147, P2148, P2149, P2150 and P2151 are not set.
- The desired fuel rail pressure does not vary more than 290 psi (2 MPa).
- The fuel injection quantity does not vary more than 2 cu.mm.

High Fuel Pressure DTC
- DTCs P0089, P0091, P0092, P0192, P0193, P0642 and P0643 are not set.
- The battery voltage is between 10-16 volts
- The engine is running.

Condition for Setting the DTC
Pressure Oscillation DTC
- The ECM detects that the oscillation of fuel feed quantity is more than a threshold. And oscillations have occurred continuously for 1000 times. (2 tests per crankshaft revolution)

High Fuel Pressure DTC
- The ECM detects that the actual fuel rail pressure is more than 28550 psi (197 MPa) for longer than 35 seconds.

OR

- The ECM detects that the actual fuel rail pressure is more than 33350 psi (230 MPa) for longer than 1 second.

Action Taken When the DTC Sets
Pressure Oscillation DTC 12,000 lbs GVW
- The ECM illuminates the service vehicle soon (SVS) lamp when the diagnostic runs and fails.
- The ECM records the operating conditions at the time the diagnostic fails. The ECM stores this information in the Failure Records.

Except 12,000 lbs GVW
- The ECM will not illuminate the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
- The ECM records the operating conditions at the time the diagnostic fails. The ECM stores this information in the Failure Records.

High Fuel Pressure DTC
- The ECM will not illuminate the MIL when the diagnostic runs and fails.
- The ECM records the operating conditions at the time the diagnostic fails. The ECM stores this information in the Failure Records.

Condition for Clearing the MIL/DTC
Pressure Oscillation DTC 12,000 lbs GVW
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic after the ECM turns OFF the SVS lamp.
- Clear the SVS lamp and the DTC with a scan tool.

Except 12,000 lbs GVW
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
- Clear the DTC with a scan tool.

High Fuel Pressure DTC
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
- Clear the DTC with a scan tool.

Diagnostic Aids
Pressure Oscillation DTC
- Make sure the fuel pressure sensor wiring is not interfering with the crankshaft position (CKP), camshaft position (CMP) sensor and fuel injector(s) wire or after-market add-on electrical equipment.

High Fuel Pressure DTC
- A sticking fuel rail pressure (FRP) regulator) may have allowed the fuel pressure to become high enough to set this DTC.
- Normal Actual Fuel Rail Pressure readings on the scan with the engine running in Park or Neutral at idle are around 3650 to 5050 psi (25 to 35 MPa) and around 14500 to 21750 psi (100 to 150 MPa) in Park or Neutral at W.O.T. (accelerator pedal full travel).
- A skewed FRP sensor value (shifted to a higher pressure) can set this DTC. The Actual Fuel Rail Pressure on the scan tool should read 0 psi (0 MPa) with the key ON and engine OFF after the engine has stopped running for a minimum of 2 minutes.
- Resistance in the FRP sensor low reference circuit can set this DTC. Ensure that the sensor low reference circuit has no resistance and the connectors are tight and free of corrosion.

NOTE:
- The Actual Fuel Rail Pressure on scan tool will only update with the engine running or one time after the key is cycled when the ignition has been turned OFF for longer than 10 seconds.
- The fuel system from the fuel tank(s) to the fuel supply pump is under a slight vacuum with the engine running. As a result, air can enter the fuel system if these connections are not tight or if there is a crack in one of the fuel hoses. Air in the fuel system will cause fuel rail pressure fluctuations especially at high engine speed and load, which may set this DTC.
- If the fuel tank is empty or near empty, air might be allowed to go into the fuel system. With air in the fuel system, smooth flow of fuel into the supply pump is interrupted and this DTC may set. Perform bleeding of fuel system after refilling.

Test Description
The numbers below refer to the step number on the diagnostic table.
7. This step checks for a fuel restriction by determining if a high vacuum is being pulled on the fuel system during normal operation.
8. This step checks for an air leak on the suction side of the fuel system by determining if a vacuum can be pulled when a fuel line is plugged.
19. This DTC indicates that the fuel pressure went high and it's possible that the pressure limiter valve did not active.

DTC P2293
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls Connector End Views or Engine Control Module (ECM) Connector End Views

Step 6:

Step 7 - 8:

Step 9 - 12:

Step 13 - 17:

Step 18 - 21: