HARNESS AS-CONSOLE 5283408 - Caterpillar

Probable Causes
Battery voltage to the primary ECM
Loss of primary ECM heartbeat signal
Diagnostic codes for the injector solenoids
Engine overspeed conditionRecommended Actions
Battery Voltage to the Primary ECM
Connect Caterpillar Electronic Technician (ET). Establish communication with the primary ECM. If communication with the primary ECM cannot be established, verify that voltage is present at the primary ECM. If voltage is not present at the keyswitch input on the primary ECM, refer to Troubleshooting, "Engine Control Switch - Test". If battery voltage is not present at the inputs on the primary ECM, refer to Troubleshooting, "Electrical Power Supply - Test".Loss of Primary ECM Heartbeat Signal
The secondary ECM will assume control of governing the engine if the primary ECM heartbeat signal to the secondary ECM is interrupted. Verify that the wire that carries the primary ECM heartbeat signal to the secondary ECM does not have an open or that the wire is not shorted. The secondary ECM will remain in control of governing until keyswitch power to the primary ECM has been cycled.Multiple Diagnostic Codes for the Injector Solenoids
If two diagnostic codes for the injector solenoids are active for a 12 cylinder engine at the same time, then the primary ECM will terminate the primary ECM heartbeat signal to the secondary ECM. If four diagnostic codes for the injector solenoids are active for a 16 cylinder engine at the same time, then the primary ECM will terminate the primary ECM heartbeat signal to the secondary ECM. The secondary ECM will assume control of governing if the primary ECM heartbeat signal to the secondary ECM is interrupted. Check for active diagnostic codes or for logged diagnostic codes for the injector solenoids. If diagnostic codes are present or if diagnostic codes were logged, refer to Troubleshooting, "Injector Solenoid - Test".Engine Overspeed Condition
If an engine overspeed occurs, the secondary ECM will assume control of governing. The secondary ECM will stop fuel injection to the engine. The secondary ECM will remain in control of governing until keyswitch power to the primary ECM has been cycled. Determine the cause for the engine overspeed. Refer to Troubleshooting, "Engine Overspeeds".