For a complete wiring diagram Refer to Section 8WWhen Monitored:Continuously while the system is active.Set Condition:The ECM is receiving a LIN bus error message.Possible CausesINTERMITTENT DTC(D509) LIN BUS CIRCUIT SHORTED TO GROUND(D509) LIN BUS CIRCUIT SHORTED TO VOLTAGEGENERATORENGINE CONTROL MODULE (ECM)Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.(Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)1. DTC IS ACTIVETurn the ignition on.With a scan tool, View DTCs.Record all DTC information.With a scan tool, Clear DTCs.Start the engine and allow it to reach normal operating temperature.Monitor the scan tool for at least 2 minutes.With a scan tool, View DTCs.Is the status Active for this DTC?YesGo To 2 NoRefer to the INTERMITTENT CONDITION Diagnostic Procedure.(Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)2. GENERATORTurn the ignition off.Disconnect the Generator harness connector.Turn the ignition on.With a scan tool, Clear DTCs.With a scan tool, View DTCs.Monitor the scan tool for at least 2 minutes.If the Generator LIN bus circuit is shorted internally, the LIN Bus DTC will not set with the Generator disconnected. If the LIN bus is shorted to voltage or ground, this DTC will remain Active.Is the status Active for this DTC?YesGo To 3NoReplace the Generator in accordance with the Service Information.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)3. (D509) LIN BUS CIRCUIT SHORTED TO GROUND

Turn the ignition off.Disconnect the Engine Control Module (ECM) harness connector.Measure the resistance between ground and the (D509) LIN Bus circuit in the Generator harness connector.Is the resistance above 1000 ohms?YesGo To 4NoRepair the (D509) LIN Bus for a short to ground.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)4. (D509) LIN BUS CIRCUIT SHORTED TO VOLTAGE

Remove the ASD Relay.Connect a jumper wire between cavity 30 and cavity 87 of the ASD Relay Connector.Turn the ignition on.Measure the voltage of the (D509) LIN Bus circuit in the Generator harness connector.Is there any voltage present?YesRepair the (D509) LIN Bus circuit for a short to voltage.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoGo To 55. ENGINE CONTROL MODULE (ECM)Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Glow Plug Module and the Engine Control Module (ECM).Look for any chafed, pierced, pinched, or partially broken wires.Look for broken, bent, pushed out or corroded terminals.Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.Look for the data to change or for the DTC to reset during the wiggle test.Refer to any Technical Service Bulletins that may apply.Were any problems found?YesRepair as necessary.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoReplace the Engine Control Module (ECM) in accordance with the Service Information.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)