SEAL KIT- 1937628 - Caterpillar

Use this procedure to troubleshoot the electrical system if a problem is suspected with the power to the engines Electronic Control Module (ECM). Use this procedure if any of the diagnostic codes in Table 1 is active or easily repeated.
Table 1
J1939 Code and Description    CDL Code and Description    Comments    
168-2
Battery Potential / Power Input #1 : Erratic, Intermittent, or Incorrect     168-2
Electrical System Voltage : Erratic, Intermittent, or Incorrect     The engine is running. The battery voltage falls below 6 VDC and the voltage returns above 9 VDC for three voltage readings in the last 7 seconds.    
168-3
Battery Potential / Power Input #1 : Voltage Above Normal     168-3
Electrical System Voltage : Voltage Above Normal     The ECM detects voltage that is above the acceptable value.    
168-4
Battery Potential / Power Input #1 : Voltage Below Normal     168-4
Electrical System Voltage : Voltage Below Normal     The ECM detects voltage that is below the acceptable value.    Probable Causes
Codes
Charging circuit
Load Test
Illustration 1 g02100347
Schematic for the electrical power supply circuitRecommended Actions
Table 2
Troubleshooting Test Steps    Values    Results    
1. Check for Codes
A. Connect Cat® Electronic Technician (ET) to the service tool connector.
B. Look for active codes that are associated with the system for the event code.
   
Diagnostic code    
Result: A -3 diagnostic code is active.
Proceed to Test Step 2.
Result: A -4 diagnostic code is active.
Proceed to Test Step 3
   
2. Check the Charging Circuit
A. Check the charging circuit. Refer to Special Instruction, REHS0354, "Charging System Troubleshooting".
   
Charging circuit    
Result: The charging system is OK.
Proceed to Test Step 3.
Result: The charging system is not OK.
There is a problem with the charging system. Make the necessary repairs. Refer to Special Instruction, REHS0354, "Charging System Troubleshooting".
   
3. Load Test the Battery
A. Load test the battery. Refer to Systems Operation and Testing and Adjusting, "Battery - Test"
   
Load test    
Result: The battery voltage is low or the battery did not pass the load test.
Recharge or replace the faulty batteries. Verify that the repair eliminates the problem.
Result: The batteries pass the load test. The measured voltage is between 11.5 VDC and 13.5 VDC for a 12 v system. The measured voltage is between 23.0 VDC and 27.0 VDC for a 24 v system.
Verify that the "System Operating Voltage Configuration" is correctly configured in the Engine ECM configuration parameters.
   If the procedure did not correct the issue, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).