VALVE GP-PUMP CONTROL 1943899 - Caterpillar

Illustration 1 g01457897
View of checking the voltageThe voltage of the PL121 is detected at the connection for the GPS antenna.Expected Result:The voltage is approximately 3.3 VDC.Results:
OK - The voltage is 3.3 VDC. Proceed to Test Step 12.
NOT OK - The voltage is greater than 3.3 VDC or less than 3.3 VDC. The measurement is incorrect.Repair: Replace the module. Verify that the system is operating correctly.STOPTest Step 12. CHECK FOR A BROKEN "OPEN" COAXIAL CABLE FOR THE VHF ANTENNAThe VHF antenna can be checked to determine if the antenna cable has a broken center conductor. With an ohmmeter, check between the VHF antenna TNC connector center conductor to the threaded metal socket at the top of the antenna mount.Note: This measurement cannot be made on the GPS antenna.See Table 1, Table 2, Illustration 2, and Illustration 3 for making resistance checks.
Table 1
Measurements for the PL121SR Antenna
263-8948, 263-7802, or 266-2861    
   Connector Center Pin for VHF Communication    Connector Outer Shield for VHF Communication    GPS Connector Center Pin    GPS Connector Outer Shield    Threaded Socket for Whip Antenna    Metal Base Antenna    
Connector Center Pin for VHF Communication     N/A     Open     N/A     N/A     Less than 3 Ω     Open    
Connector Outer Shield for VHF Communication     Open     N/A     N/A     Less than 1 Ω     N/A     Less than 1 Ω    
GPS Connector Center Pin     N/A     60 to 70 Ω     N/A     60 to 70 Ω     N/A     60 to 70 Ω    
GPS Connector Outer Shield     N/A     N/A     60 to 70 Ω     N/A     N/A     Less than 1 Ω    
Table 2
Measurements for the PL121SR Antenna
284-8533, 310-2393, 284-8532, 310-2391, 284-8531, or 310-2392    
   Connector Center Pin for VHF Communication    Connector Outer Shield for VHF Communication    GPS Connector Center Pin    GPS Connector Outer Shield    Threaded Socket for Whip Antenna    Metal Base Antenna    
Connector Center Pin for VHF Communication     0 Ω     Open     Open     Open     0 Ω     Open    
Connector Outer Shield for VHF Communication     Open     0 Ω     Open     Open     Open     0 Ω    
GPS Connector Center Pin     Open     Open     0 Ω     6 to 10 M Ω     Open     Open    
GPS Connector Outer Shield     Open     Open     6 to 10 M Ω     0 Ω     Open     Open    Note: The antenna is shipped from the supplier with a "removable strength" thread lock. The thread lock is located between the antenna whip and the base adapter. If the antenna whip is removed, Caterpillar recommends clearing any debris from the base by cleaning the threads. Use a "removable strength" thread lock when you attach the antenna whip again. Caterpillar recommends using 185-3996 Thread Lock Compound.
Illustration 2 g01452981
Illustration 3 g01136183
Resistance checks for the VHF antenna and GPS antenna (1) Locknut for the antenna (Hard mount), lockwasher, and threaded