BEARING ASSEMBLY-- IDLER 4L8308 - Caterpillar

Table 1
EFR Diagnostic Feedback PWM Signals    
PWM Duty Cycle Percentage     Indication to the Drivetrain ECM    
Less than 5%     Feedback line short to ground.    
10%     EFR not enabled, power, and PWM are received - waiting for "EFR Enable" command.    
20%     EFR in Standby - Internal boost voltage is high with output command disabled.    
30%     Input voltage out of range    
40%     Output short circuit - Output shorted high or low    
50%     Normal operation - No faults present.    
60%     Output open circuit.    
70%     Output current too high    
80%     PWM command from Drivetrain ECM out of the normal range (3% to 97%)    
90%     Undefined internal EFR fault.    
100%     Feedback circuit shorted to another voltage source.    During machine operation, the Excitation Field Regulator (EFR) supplies 144.0 DC volts to the Generator exciter windings through current drive circuits that are connected between the EFR and the Generator low voltage enclosure. These circuits are connected in the four contact exciter circuit harness connectors at the EFR and at the Generator enclosure. After machine shutdown, these circuits can contain hazardous voltage levels for approximately 5 minutes. After Engine shutdown, wait for at least 5 minutes before disconnecting the four contact exciter circuit connectors at the EFR and at the enclosure or before entering the Generator low voltage enclosure. Always use a multimeter to verify that there is 50.0 VDC or less at any exposed exciter circuit contacts before any other action is taken.Before proceeding with this procedure, ensure that the MID 081 CID 3009 FMI 03 diagnostic code is active.Test Step 1. CHECK THE CURRENT DRIVE CIRCUIT FOR A SHORT
Turn the battery disconnect switch to the OFF position. Turn the key start switch to the OFF position. Wait for at least 5 minutes.
On the left-hand side Generator enclosure, disconnect the four contact connector that contains the two current output circuits. Examine the contacts on the harness connector and on the mating enclosure connector. Ensure that the contacts are clean, dry, and in good condition.
Turn the battery disconnect switch to the ON position. Turn the key start switch to the ON position. Do not start the Engine.
Use a multimeter to perform the following voltage checks:
At the four-contact harness connector, check for system voltage between the exciter current drive positive (+) contact C and the exciter current drive negative (-) contact B. While observing the measurement, wiggle and manipulate the harness connector.
At the mating enclosure connector, check for system voltage between the exciter positive (+) contact C and the exciter negative (-) contact B.Expected Result:At least one of the voltage measurements between the exciter circuits measured a voltage that is greater than 3.0 VDC.Results:
YES - A voltage of greater that 3.0 VDC was observed for one if the measurements.Repair: If the voltage measurement between the exciter current output circuits at the harness connector measured greater that 3.0 VDC:
The most likely cause is