SPN 94 - FMI 2 (Fault Code 268)

Injector Metering Rail 1 Pressure - Data Erratic, Intermittent, or Incorrect

Fuel Pressure Sensor Circuit

Fault Code: 268
PID(P), SID(S): P094
SPN: 94
FMI: 2
Lamp: Amber

REASON: Injector Metering Rail 1 Pressure - Data Erratic, Intermittent, or Incorrect. The ECM has detected that the fuel pressure signal is not changing.

EFFECT: The ECM will estimate fuel pressure, and power is reduced.

Circuit Description:
The fuel pressure sensor contains supply, signal, and return pins. The ECM provides +5 VDC to the fuel pressure sensor. This +5 VDC power supply is a shared supply. Other sensors on this circuit are the intake manifold pressure sensor, backup engine position sensor.

Component Location:
The fuel pressure sensor is located in the rail fuel on the air intake side of the engine.

Shop Talk:
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:
• Intake manifold pressure sensor
• Backup engine position sensor
• Fuel pressure sensor.

Read More:
SPN 98 - FMI 1 (Fault Code 253)
SPN 647 - FMI 4 (Fault Code 245)


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