RING-BACKUP 1583027 - Caterpillar

System Operation Description:Use this procedure to troubleshoot the electrical system if a problem is suspected with the circuit for one of the Pulse Width Modulated sensors (PWM sensors) or if one of the diagnostic codes in Table 1 is active or easily repeated.
Table 1
Diagnostic Codes Table    
Description    Conditions which Generate this Code    System Response    
102-3 Boost Pressure Sensor : Voltage Above Normal     The Electronic Control Module (ECM) has detected a frequency of less than 375 Hz for the sensor's PWM signal.     The code is logged.
The alarm output is activated.
The shutdown output is activated.
The engine is shut down.    
102-8 Boost Pressure Sensor : Abnormal Frequency, Pulse Width, or Period     The ECM has detected a frequency that is greater than 625 hertz for the sensor's PWM signal.
or
The duty cycle is greater than 98 percent or the duty cycle is less than 2 percent for the sensor's PWM signal.    
106-3 Air Inlet Pressure Sensor : Voltage Above Normal     The ECM has detected a frequency of less than 375 Hz for the sensor's PWM signal.    
106-4 Air Inlet Pressure Sensor : Voltage Below Normal     The ECM has detected a voltage on the circuit that is less than 0.2 volts for five seconds.    
106-8 Air Inlet Pressure Sensor : Abnormal Frequency, Pulse Width, or Period     The ECM has detected a frequency that is greater than 625 Hz for the sensor's PWM signal.
or
The duty cycle is greater than 95 percent or the duty cycle is less than 5 percent for the sensor's PWM signal.    
109-3 Engine Coolant Outlet Pressure Sensor : Voltage Above Normal     The ECM has detected a frequency of less than 375 Hz for the sensor's PWM signal.     The code is logged.
The alarm output is activated.    
109-8 Engine Coolant Outlet Pressure Sensor : Abnormal Frequency, Pulse Width, or Period     The ECM has detected a frequency that is greater than 625 Hz for the sensor's PWM signal.
or
The duty cycle is greater than 95 percent or the duty cycle is less than 5 percent for the sensor's PWM signal.    The following PWM sensors are used by this engine:
Boost pressure
Engine coolant pressure (outlet)
Intake manifold pressure
Illustration 1 g01423130
Components for the PWM sensors (1) Analog pressure sensor (2) Signal converterThe PWM sensor circuit consists of an analog pressure sensor and a signal converter. The signal converter receives a 8.0 0.4 VDC regulated voltage from the ECM. The signal converter provides 5.0 0.25 VDC to the analog sensor. The analog pressure sensor provides an analog signal to the signal converter that represents the pressure that is being sampled. The signal converter converts the analog signal to a PWM signal and the converter then transmits the signal to the ECM.The signal converter generates a PWM signal that is in a specific range of duty cycle that is sent to the ECM. This range is directly related to the pressures that are sampled by the pressure sensor. As the