Cummins ISB CM850 (2003-06) Fault Code: 551 (SSS) PID: SID 230 SPN: 558 FMI: 4 Accelerator Pedal or Lever Idle Validation Circuit – Voltage Below Normal or Shorted to Low Source. No voltage detected simultaneously on both the idle validation off-idle and on-idle circuits. 1)This fault code is usually caused by a short circuit to ground in the harness, an uncalibrated accelerator pedal or lever assembly, or a miswired idle validation switch.2)When installing a new accelerator pedal or lever assembly, it must be calibrated before operating the engine. To calibrate, turn the keyswitch to the ON position, and fully depress...

Cummins ISB CM850 (2003-06) Fault Code: 553 PID: 157 SPN: 157 FMI: 0 Injector Metering Rail 1 Pressure – Data Valid but Above Normal Operational Range – Moderately Severe Level. The ECM has detected that fuel pressure is higher than commanded pressure. A fuel pump actuator with excessive leakage or a damaged inboard o-ring will result in high fuel rail pressures at idle or light load. If the fuel pump actuator exhibits excessive leakage, it is possible that the fuel rail pressure will reach the opening pressure of the fuel rail pressure relief valve and Fault Code 449 may also...

Cummins ISB CM850 (2003-06) Fault Code: 554 PID: 157 SPN: 157 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 electronic control module (ECM) detects the 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...

Cummins ISB CM850 (2003-06) Fault Code: 559 (ISB) PID: 157 SPN: 157 FMI: 1 Fuel Pump Delivery Pressure Low – Data Valid but Below Normal Operational Range – Moderately Severe Level. The ECM has detected that fuel pressure is lower than commanded pressure. Possible causes: 1)High inlet restriction2)Excessive air in fuel3)Loss of fuel prime during cranking4)Plugged fuel filter5)Low lift pump pressure6)Stuck or restricted electronic fuel control actuator7)System return (excessive return flow from the injector, high-pressure pump, or rail pressure relief valve)8)Tampering. If the drain line is restricted completely, the high pressure fuel pump will be damaged, causing internal leakage. Prior...

Cummins ISB CM850 (2003-06) Fault Code: 559 (ISC) PID: 94 SPN: 94 FMI: 0 Injector Metering Rail 1 Pressure – Data Valid but Below Normal Operational Range – Moderately Severe Level. The ECM has detected that fuel pressure is lower than commanded pressure. If the engine will not start and Fault Code 559/2215 becomes active during cranking, but no speed sensor fault codes exist, monitor the fuel rail pressure with INSITE? electronic service tool. If the rail pressure is low, check the following: 1)Fuel system prime (make sure there is fuel in the tanks and the system is primed)2)Fuel lift...