Circuit DescriptionThe intake air heater improves starting and white smoke control in cold ambient conditions.The ECM controls relays that switch power to the air heater. There are two heating coils in theheater that are individually controlled by the ECM. Component LocationThe intake air heater is located at the air inlet connection into the intake manifold. The locationof the heater relays will vary with the OEM. Shop Talk1) These faults could also indicate the intake air heater circuits are shorted to battery (+).This would command the grids to be on full time. This will drain the batteries, burn outgrids, and/or destroy...

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 engine position sensor (EPS), the intake manifold pressure sensor, and the oil pressuresensor are powered by the same +5-VDC source and the same return in the electronic controlmodule (ECM). This supply is also used to operate the intake manifold temperature andcoolant temperature sensors. Component LocationThe +5-VDC sensor supply circuit is located in the sensor harness. See Section E of thismanual for the sensor locations. Shop TalkThese faults could also cause high- or low-voltage faults on the coolant temperature and intakemanifold temperature sensors. Cummins ISB CM550 (1990-94) Fault Code: 385 PID: SID 232 SPN: 620 FMI: 1 Remote Accelerator...

Circuit DescriptionThe engine position sensor (EPS), the intake manifold pressure sensor, and the oil pressuresensor are powered by the same +5-VDC source and the same return in the electronic controlmodule (ECM). This supply is also used to operate the intake manifold temperature andcoolant temperature sensors. Component LocationThe +5-VDC sensor supply circuit is located in the sensor harness. See Section E of thismanual for the sensor locations. Shop TalkThese faults could also cause high- or low-voltage faults on the coolant temperature and intakemanifold temperature sensors. Cummins ISB CM550 (1990-94) Fault Code: 386 PID: SID 232 SPN: 620 FMI: 3 Sensor Suppy...