TRACK AS 4659223 - Caterpillar

Illustration 3 g00896288
Harness connector for the PWM sensors
(A) 8 volt supply
(B) Return
At the harness connector for the suspect sensor, measure the voltage between terminals (A) and (B). Expected Result:The voltage is between 7.6 VDC and 8.4 VDC.Results:
OK - The voltage is within the specification. The correct voltage is present at the sensor connector. Proceed to Test Step 5.
Not OK - The voltage is not within the specification. The correct voltage is not present at the sensor connector. The correct voltage must be present at the sensor connector in order to continue this procedure.Repair: Verify that the wiring and/or connectors are OK. Repair any faulty wiring and/or connectors, when possible. Replace any faulty wiring and/or connectors, if necessary. Refer to Troubleshooting, "Electrical Connectors - Inspect".STOPTest Step 5. Verify that +Battery Voltage is Not Present in the Signal Wire
Illustration 4 g00896299
Harness connector for the PWM sensors
(B) Return
(C) Signal
At the harness connector for the suspect sensor, measure the voltage between terminal (B) and terminal (C). Expected Result:The voltage is between 7.0 VDC and 8.0 VDC.Results:
OK - The voltage is between 7.0 VDC and 8.0 VDC. The battery voltage is not present in the signal wire. Proceed to Test Step 6.
Not OK - The voltage is approximately equal to the battery voltage. The signal wire is probably shorted to the battery between the sensor and the ECM.Repair: Repair the harness, when possible. Replace the harness, if necessary.STOP
Not OK - The voltage is approximately 0 volts. The signal wire is probably shorted to ground between the sensor and the ECM.Repair: Repair the harness, when possible. Replace the harness, if necessary.STOPTest Step 6. Check the Signal at the Sensor
Set the engine control to the OFF/RESET mode.
Remove the signal wire for the suspect sensor from terminal C of the sensor connector.
Use a multimeter that is capable of measuring both the duty cycle and the frequency. Connect the multimeter to terminal (B) of the sensor connector and the signal wire that was removed from terminal (C) of the sensor connector.
Set the engine control to the STOP mode.
Measure the duty cycle and the frequency of the suspect sensor.
Return all wiring to the original configuration. Expected Result:The duty cycle is between 5 percent and 95 percent.The frequency is between 400 and 600 Hz.Results:
OK - The duty cycle is between 5 percent and 95 percent. The frequency is between 400 and 600 Hz. A valid signal is produced by the sensor. Proceed to Test Step 7.
Not OK - The duty cycle or the frequency is incorrect. The sensor is receiving the correct supply voltage but the sensor is not producing a valid signal.Repair: Perform the following steps:
Thoroughly inspect the connector for the sensor according to Troubleshooting, "Electrical Connectors - Inspect".
Check the duty cycle and the frequency of the sensor signal again.
If the duty cycle and the frequency of the sensor signal are incorrect, set the engine control to the OFF/RESET mode.
Disconnect the sensor. Connect a sensor that is known to be good. Do not install the new sensor into the engine