SWING MOTOR 4I9649 - Caterpillar

Illustration 1 g01155513
Schematic of the body position sensor
This diagnostic code is associated with the body position sensor. This diagnostic code is recorded when the Power Train/Chassis Electronic Control Module (ECM) reads the Pulse Width Modulated (PWM) signal from the sensor. Note: This diagnostic code is usually an intermittent condition. The diagnostic code may be active or the diagnostic code may not be active.The possible causes of this condition are listed:
The signal circuit is shorted to the +battery circuit or shorted to ground intermittently.
The signal circuit is open intermittently or the sensor is disconnected.
The sensor may have failed.Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear these diagnostic codes when the original diagnostic code has been corrected. Ensure that the diagnostic code of CID 1175 FMI 08 is active before performing this procedure.Note: Use the 146-4080 Digital Multimeter for the measurements in this procedure.System Response:The body snub function for the hoist system does not operate properly when the body is lowered. The gear of the machine is limited. The gear is limited to the current setting for the gear limit function. The hoist system will operate properly after the diagnostic code has been corrected.Test Step 1. CHECK THE OPERATION OF THE SENSOR.
Turn the battery disconnect switch and the key start switch to the ON position.
Access the Caterpillar Electronic Technician (ET). View the display that is shown for the PWM duty cycle of the sensor signal. For more information about the ET, see Systems Operation, Troubleshooting, Testing and Adjusting, "Service Tools".
Disconnect the machine harness from the sensor. Observe the display and make a note of the display that is showing for the PWM duty cycle of the sensor signal.
At the machine harness for the sensor, install a jumper wire from contact B (wire 202-BK(Black)) to the signal contact C (wire E750-PU(Purple)). Observe the display and make a note of the display for the duty cycle of the sensor signal. Expected Result:The duty cycle that is shown for step "C." should be "OPEN/SHORTED HIGH". The duty cycle that is shown for step "D." should be "SHORTED TO GROUND".Results:
YES - The duty cycle for Step "C." does read "OPEN/SHORTED HIGH" and the duty cycle for Step "D." does read "SHORTED TO GROUND". Proceed to Test Step 2.
NO - The duty cycle for Step "C." does not read "OPEN/SHORTED HIGH" and the duty cycle for Step "D." does not read "SHORTED TO GROUND".Repair: The sensor has failed. Replace the sensor.STOPTest Step 2. CHECK THE SIGNAL CIRCUIT FOR AN OPEN.
Turn the key start switch and the battery disconnect switch to the OFF position.
The sensor remains disconnected from the machine harness.
Disconnect the J1 and J2 machine harness connectors from the ECM.
At the machine harness connector J1 and J2, measure the resistance from contact J2-16 (wire E750-PU(Purple)) to all possible sources of frame ground. Expected Result:The resistance should be less than 5 ohms.Results:
YES - The resistance is less than 5 ohms. The machine harness is correct. Proceed to