SWEEP AS-LH 8E9609 - Caterpillar

Table 2
Continuity Checks and Results for the Engine Control Switch    
Switch Position     Terminal Locations     Result    
OFF/RESET     P1-31 and P1-61     No continuity    
P1-31 and P1-62
P1-31 and P1-64
AUTO     P1-31 and P1-61     No continuity    
P1-31 and P1-62
P1-31 and P1-64 Continuous    
STOP     P1-31 and P1-61     Continuous    
P1-31 and P1-62 No continuity    
P1-31 and P1-64
START     P1-31 and P1-61     No continuity    
P1-31 and P1-62 Continuous    
P1-31 and P1-64 No continuity    Connect the J1/P1 ECM connectors.Expected Result:Each of the continuity checks agree with the results that are given in the Table.Results:
OK - The continuity checks agree with the results that are given. There is not a problem with the engine control switch or the circuit for the switch. Proceed to Test Step 5.
Not OK - At least one of the continuity checks did not agree with the results that are given.Repair: There is a problem in the harness or in a connector that is for the engine control switch. The problem could be in the harness that is inside the terminal box for the master ECM. There may be a problem with the engine control switch. Perform the necessary repairs. Replace parts, if necessary. Verify that the repair eliminates the original problem.STOPTest Step 5. Check for Keyswitch Power at the ECM connector
Ensure that the engine will not crank during this procedure. Remove the pressurized air supply from the air start system. Purge any remaining pressurized air from the system.
Restore electrical power to the engine.
Use two 7X-1710 Multimeter Probes at the terminal locations of the P1 and P3 ECM connectors in order to check the input voltage for the keyswitch circuit.Note: During these measurements, wiggle the harness in order to check for an intermittent problem. Be sure to wiggle the harness near each of the connections.
Place the engine control switch in each of the switch positions and check for voltage at the terminal locations that are given below. Check your results with the results that are given:
Table 3
Voltage Checks and Results for the Keyswitch Input    
Switch Position     Terminal Locations at P1 and P3     Result    
OFF/RESET     Terminal 69 and Terminal 70     0 volts    
AUTO     Terminal 69 and Terminal 70     22 VDC to 29 VDC    
STOP     Terminal 69 and Terminal 70     22 VDC to 29 VDC    
START     Terminal 69 and Terminal 70     22 VDC to 29 VDC    
Turn the engine control switch to the OFF/RESET position. Remove the electrical power from the engine.Expected Result:The voltage checks are within the specifications.Results:
OK - The voltage checks are within the specifications.Repair: Start the engine and run the engine. If the original problem is not resolved, the master ECM may have a problem. Perform the following procedure:Temporarily install a new master ECM. Refer to Troubleshooting, "ECM - Replace".If the problem is resolved with the new ECM, install the original ECM and verify