FITTING 4L6186 - Caterpillar

Isolating The Problem
Refer to System Operation Testing and Adjusting, KENR8977, "Electrical Connector - Inspect" section for "Step 1" and "Step 2".
Ensure that the cables for the receiver are not damaged. Ensure that all connectors are secure with no bent pins and/or broken pins.
Check the "GPS Diagnostics" for the receiver. Refer to System Operation Testing and Adjusting, KENR8977, "Operational Problems" section.
Exchange the GPS receiver with a functioning GPS receiver if available.Low Accuracy (GPS)
The GPS receiver is generating positions with errors that exceed the current GPS error limit set in the AccuGrade system.Probable Causes
Power to the GPS receiver was recently applied or cycled
Poor satellite geometry due to the GPS constellation or from physical obstructions
Poor radio coverage
Radio receiving other base station corrections
The machine is a long distance from the base station
GPS receiver fault
Incorrect "GPS Error Limit" set in the AccuGrade system (consult your supervisor)
Insufficient satellitesIsolating The Problem
Confirm that the GPS receiver is receiving power and that the connectors are secure.
Ensure that the antenna cables are not damaged and that all connectors are secure with no bent of broken pins.Refer to Testing and Adjusting, "Electrical Connector - Inspect"
Check the "GPS diagnostics" information. Refer to Systems Operation, Troubleshooting and Testing & Adjusting, "Operational Problems" for details of running receiver diagnostics. Verify the left antenna values for "Satellites Used", "PDOP" and "GPS error". For accurate GPS positions to be generated you need 5 or more satellites and the "PDOP" less than 7. As the "PDOP" decreases and the number of "L1" and "L2" satellites increase the "GPS error" will decrease. Check the status of the right receiver.
Ensure that the GPS receivers are not obstructed by buildings, trees, or other objects that would impair the line of sight for the GPS receivers.
Verify that, on the "Radio Data Link" screen, integrity is over 85 percent. Intermittent or sporadic corrections can result in increased GPS position error.
Confirm that the "GPS Error Limit" is set at the correct value. If the type of work permits you can adjust the "GPS Error Limit" to be greater than the current GPS position error as seen in the "diagnostics".Note: Always consult the site manager before you change the "GPS Error Limit".V. Low Accuracy (GPS)
The GPS receiver is tracking satellites and sending position data to the display in an appropriate format, but the receiver is generating an autonomous GPS position solution.Probable Causes
Base station GPS receiver configuration, power, or cables
Base station radio configuration, power, or cables
Machine GPS receiver configuration
Machine radio configuration, power, or cables
Receiver fault
Jamming of the radio. This may be caused by close proximity to a powerful transmitter such as a radio, microwave, or cellular tower.
Receiving corrections from another base and radio network. Isolating The Problem
Unplug your base radio and see if your machine radio will synchronize. If the machine radio does synchronize, there is a duplicate data radio network causing interference.
Change your radio network for all on site radios.
Check the GPS status of any other machines on site. If these machines also show the "V. Low Accuracy" message (that is, autonomous)