Circuit DescriptionThe accelerator pedal assembly with accelerator position sensor relays the acceleratorpercentage requested by the operator to the electronic control module (ECM). Percentaccelerator is used by the ECM to determine fueling. In order for the accelerator positionsensor to function properly, it is necessary that a good +5-VDC supply voltage is available. Component LocationThe accelerator position sensor is located on the accelerator pedal inside the vehicle cab. Cummins ISB CM550 (1990-94) Fault Code: 443 PID: 91 SPN: 620 FMI: 3 Accelerator Position Sensor Circuit Cummins ISB CM550 (1990-94) Fault Code: 442 PID: 168 SPN: 168 FMI: 0 Unswitched Battery Supply Circuit...

Circuit DescriptionThe remote accelerator supply circuit supplies +5 VDC for the remote accelerator and thecoolant level sensor. These circuits are connected inside the ECM. Faults on these circuitscould also affect the operation of the WIF sensor. These are all OEM options and often do notapply to your specific vehicle. NOTE: The connector pin letters shown for the accelerator pedal wiring in thesetroubleshooting steps are examples of representative sensors. The connector pin assignmentscan vary with equipment manufacturer, but the base troubleshooting logic will still apply. Component LocationThe remote accelerator position sensor is located on the remote accelerator control assemblysomewhere outside the...

Circuit DescriptionThe remote accelerator supply circuit supplies +5 VDC for the remote accelerator and thecoolant level sensor. These circuits are connected inside the ECM. Faults on these circuitscould also affect the operation of the WIF sensor. These are all OEM options and often do notapply to your specific vehicle. NOTE: The connector pin letters shown for the accelerator pedal wiring in thesetroubleshooting steps are examples of representative sensors. The connector pin assignmentscan vary with equipment manufacturer, but the base troubleshooting logic will still apply. Component LocationThe remote accelerator position sensor is located on the remote accelerator control assemblysomewhere outside the...

Circuit DescriptionThe intake manifold air temperature sensor is used by the electronic control module (ECM) tomonitor the temperature of the engine intake air. The intake air temperature is used by theECM for the engine protection system, and the timing and fueling control.Component LocationThe intake manifold temperature sensor is located on the side of the intake manifold, towardthe rear of the cylinder head, near cylinder No. 6. Shop TalkThis is a warning fault code. If the intake manifold air temperature continues to rise, Fault Code155 will become active and shut down the engine. Possible causes:1) clogged, dirty, inadequate capacity air cleaner...

Circuit DescriptionThe auxiliary speed input is a frequency signal from an auxiliary speed or pressure pickup. It issent to the electronic control module (ECM) and is used to control the engine speed. Auxiliaryreference speed is based on the throttle position. Component LocationThe auxiliary speed or pressure pickup device location is dependent on the original equipmentmanufacturer’s (OEM) application. Refer to OEM manual for component location. Shop TalkThe auxiliary speed governor controls engine speed based on a measured auxiliary speed orpressure. The auxiliary speed governor feature must be enabled in the calibration and setproperly for speed or pressure, depending on the OEM...