Cummins ISB CM850 (2003-06) Fault Code: 268 PID: 94 SPN: 94 FMI: 2 Injector Metering Rail 1 Pressure – Data Erratic, Intermittent, or Incorrect. The ECM has detected that the fuel pressure signal is not changing.

Cummins ISB CM850 (2003-06) Fault Code: 268 PID: 94 SPN: 94 FMI: 2 Injector Metering Rail 1 Pressure – Data Erratic, Intermittent, or Incorrect. The ECM has detected that the fuel pressure signal is not changing.

This fault code can become active any time the engine is loaded and the ECM detects that fuel pressure in the rail fuel is not changing. This fault code will become inactive whenever the ECM is powered down or if the ECM detects that the engine is loaded and the fuel pressure is changing normally. If there are many inactive counts of this fault code or if the fault is not repeatable, look for signs of tampering to the fuel pressure sensor circuit. If the fault code occurs intermittently (can not be reproduced during a road test), then inspect each of the following for poor connections or damage:

1)Intake manifold pressure sensor
2)Backup engine position sensor
3)Fuel pressure sensor.

Possible repairs:

1)Replace the rail fuel pressure sensor.
2)Repair or replace the engine harness.
3)Replace the ECM.