COUNTERWEIGHT GP 1428830 - Caterpillar

Illustration 14 g00901913
Harness side of the P4 connector for the slave ECM (P4-56) 8 volt supply for the detonation sensors (P4-57) 8 volt supply for the detonation sensors
If you are troubleshooting an 8 volt problem with the master ECM, use a 151-6320 Wire Removal Tool to remove the wires from the following terminals:
(P1-4)
(P2-56)
(P2-57)
(P4-56)
(P4-57)
If you are troubleshooting an 8 volt problem with the slave ECM, use a 151-6320 Wire Removal Tool to remove the wires from the following terminals:
(P4-56)
(P4-57)
Switch the 16 amp circuit breaker ON. Set the engine control to the STOP mode.
Wait for at least 30 seconds and then observe the "Active Diagnostics" screen on Cat ET. Determine if a 41-03 code or a 41-04 code is active.Expected Result:No active codesResults:
No codes - The 41-03 code or the 41-04 code is not active. Disconnecting all of the 8 volt wiring from the ECM eliminated the active "8 Volt DC Supply" diagnostic code. There is a problem in a connector and/or the wiring in a harness. Proceed to Test Step 5.
Active code - There is an active 41-03 or 41-04 code. Disconnecting all of the 8 volt wiring from the ECM did not eliminate the active "8 Volt DC Supply" diagnostic code. There may be a problem with an ECM.Repair: Set the engine control to the OFF mode. Switch the 16 amp circuit breaker OFF.Insert all of the terminals that were removed. Pull on the wires in order to verify that the terminals are fully inserted into the connector.It is unlikely that the ECM has failed. Exit this procedure and perform this procedure again. If the problem is not resolved, perform the following steps:Temporarily install a new ECM. Refer to Troubleshooting, "Replacing the ECM".If the problem is resolved with the new ECM, install the original ECM and verify that the problem returns. If the new ECM operates correctly and the original ECM does not operate correctly, replace the original ECM. Refer to Troubleshooting, "Replacing the ECM".STOPTest Step 5. Check the Wiring Harnesses on the Left Side of the Engine
Set the engine control to the OFF mode. Switch the 16 amp circuit breaker OFF.
Insert all of the terminals that were removed. Pull on the wires in order to verify that the terminals are fully inserted into the connector.
Disconnect all of the 8 volt sensors.
Disconnect the P1 connector and the P2 connector for the master ECM.
Illustration 15 g00980962
ECM side of the master ECM connectorsNote: For the functions of the terminals, refer to Table 1.
Measure the resistance between the terminals that are listed in Table 1.During each measurement, wiggle the harnesses in order to check for an intermittent problem. Be sure to wiggle the wires near each of the connectors.
Table 1
Points for the Measurement of Resistance for the Left Side of the Engine    
Connector and Terminal     Connector and Terminal    
P1-4 (8 volt supply)     P1-5 (Digital return)    
P1-10 (Digital sensor signal)
P1-12 (Digital sensor signal)
P2-68 (Digital sensor signal)
P2-56 (8 volt supply)     P2-36 (Detonation sensor signal)    
P2-37 (Detonation sensor