Service Manual

7. Troubleshooting 10-2019
148 A062J683 (Issue 1)Copyright © 2019 Cummins Inc.
• Oil viscosity
• Iced or corroded brushes or slip rings (open/shorted excitation circuit)
• Open/shorted quad sense or quad winding
• Failed AVR/field flash circuit
• Slow cranking speed
Diagnosis and Repair:
1. Check the last fault recorded.
• If this fault has not been repaired, troubleshoot that fault.
2. Verify that the fuel valve external to the generator set is open.
3. Disconnect the generator set control P1 connector.
4. Verify that the P1 and P2 pin sockets are fully inserted and inspect the pin
socket condition for corrosion and acceptable condition of contact wipers. To
check contact wipers, use one of the devices below:
• A mating pin connector
• A pin gauge the same size as the mating control connector pin (0.045 in)
• Any suitable device that will not damage the inside contact wipers of the
pin socket
If necessary:
• Clean, repair or replace any pin sockets.
• Fully insert any partially inserted pin sockets.
5. Inspect the condition of P1 and P2 pins on the control board. If they are
damaged or severely corroded, clean or repair if possible, or replace the control
board.
6. When reconnecting the harness plug to the connector, ensure that the pair are
fully seated next to each other.
7. Reconnect the P1 connector and test-run the generator set for fault occurrence.
8. Verify the engine rotation manually.
• Repair engine damage if necessary.
9. Measure the DC voltage at the starter during start attempt.
• Repair wire connections if necessary.
• Replace the starter and solenoid assembly if necessary.
10. Check air filter cleanliness.
• Replace the air filter if necessary.
11. Check for any external damage to the exhaust system and listen for any
unusual noises that may reside in the system.
• Repair or replace exhaust components if necessary.