Circuit/System Testing

Dual Battery Control Module Circuit Malfunction

1. Test for less than 0.5 V between the C1B Battery - Auxiliary positive terminal and B+ circuit connector X4 terminal 1 at the X50D Fuse Block - Battery with the ignition in the START position.
   • If 0.5 V or greater 

     Replace C1B Battery - Auxiliary positive cable.

   • If less than 0.5 V 
CAUTION:

Do not disconnect the K125 Dual Battery Control Module harness connector with the batteries connected. Leaving the module disconnected for an extended period of time can lead to a significant increase in temperature and damage to the module.

2. Ignition OFF, disconnect the C1 and C1B battery (disconnect negative cable of each battery).
3. Disconnect the harness connector at the at the K125 Dual Battery Control Module.
4. Test for less than 10 Ω between ground circuit terminal 4 and ground.
   • If 10 Ω or greater 
   1. Test for less than 2 Ω in the ground circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, repair the open/high resistance in the ground connection.
   • If less than 10 Ω 
5. Disconnect the F18UA 5A fuse.
6. Test for infinite resistance between the ignition circuit terminal 3 and B+ terminal of the C1 Battery.
   • If less than infinite resistance 

     Repair the short to voltage on the circuit.

   • If infinite resistance 
7. Test for infinite resistance between the ignition circuit terminal 3 and ground.
   • If less than infinite resistance 

     Repair the short to ground on the circuit.

   • If infinite resistance 
8. Test for less than 2 Ω in the ignition circuit end to end.
   • If 2 Ω or greater 

     Repair the open/high resistance in the circuit.

   • If less than 2 Ω 
9. Disconnect the X2 harness connector at the K20 Engine Control Module and disconnect the KR27 Starter Relay.
10. Test for infinite resistance between the control circuit terminal 2 at the K125 Dual Battery Control Module and B+.
    • If less than infinite resistance 

      Repair the short to voltage on the circuit.

    • If infinite resistance 
11. Test for infinite resistance between the control circuit terminal 2 at the K125 Dual Battery Control Module and ground.
    • If less than infinite resistance 

      Repair the short to ground on the circuit.

    • If infinite resistance 
12. Test for less than 2 Ω in the control circuit end to end.
    • If 2 Ω or greater 

      Repair the open/high resistance in the circuit.

    • If less than 2 Ω 
13. Disconnect the X3 harness connector at the K20 Engine Control Module and disconnect the F11UA fuse.
14. Test for infinite resistance between the control circuit terminal 1 at the K125 Dual Battery Control Module and B+.
    • If less than infinite resistance 

      Repair the short to voltage on the circuit.

    • If infinite resistance 
15. Test for infinite resistance between the control circuit terminal 1 at the K125 Dual Battery Control Module and ground.
    • If less than infinite resistance 

      Repair the short to ground on the circuit.

    • If infinite resistance 
16. Test for less than 2 Ω in the control circuit end to end.
    • If 2 Ω or greater 

      Repair the open/high resistance in the circuit.

    • If less than 2 Ω 
17. Test or replace the K125 Dual Battery Control Module.