FLANGE 5N1845 - Caterpillar

System Operation Description:The master Electronic Control Module (ECM) contains the logic and the outputs for control of starting and shutdown of the engine. The logic for starting and stopping is customer programmable. The logic responds to inputs from the following components: engine control switch, emergency stop switch, remote start switch, data link and other inputs.The fuel control relay is energize-to-run. To enable fuel flow to the engine, the relay for the Gas Shutoff Valve (GSOV) must be energized. The master ECM provides +battery voltage to the relay for the GSOV when the logic determines that fuel is required for engine operation. For engine shutdown, the master ECM removes the voltage from the fuel control relay. This stops the fuel flow.The output circuit for the relay for the GSOV includes the emergency stop switch. The emergency stop switch has three sets of contacts. One set of contacts is for the GSOV. The contacts are normally closed. Pressing the emergency stop switch opens all of the sets of contacts. This removes the voltage from the fuel control relay. This stops the fuel flow.The output circuit for the relay for the GSOV also includes the J19 connector. A 168-2028 Wiring Harness or a 237-5110 Wiring Harness must be connected to the J19 connector in order for the engine to start. The wiring harness must remain connected in order for the engine to run.Logged diagnostic codes provide a historical record. Before you begin this procedure, use the Caterpillar Electronic Technician (ET) to print the logged codes to a file.The most likely causes of a diagnostic code are a poor electrical connection or a problem in a wiring harness. The next likely cause is a problem with the GSOV. The least likely cause is a problem with the master ECM.The troubleshooting procedure may generate additional diagnostic codes. Keep your mind on correcting the cause of the original diagnostic code. Clear the diagnostic codes after the problem is resolved.17-12 Diagnostic CodeUnder normal conditions, the master ECM shuts down the engine by removing electrical power from the GSOV. The master ECM continues the ignition until the engine reaches zero rpm. If the GSOV is working properly, the engine should reach zero rpm soon after the electrical power is removed from the GSOV.If the engine continues to operate because of a faulty GSOV, the master ECM will disable the ignition. The master ECM will also activate a 17-12 diagnostic code.
Illustration 1 g00997783
Schematic of the output circuit for the fuel control relayTest Step 1. Inspect the Electrical Connectors and Wiring
Illustration 2 g00987150
Terminal box for the master ECM (1) J2/P2 connectors for the master ECM (2) J13/P13 connectors for the fuel control relay (3) Emergency stop switch (4) Wiring harness (5) 16 amp circuit breaker (6) Wiring harness for the customer
Set the engine control to the OFF/RESET mode. Switch the 16 amp circuit breaker OFF.Note: For the following steps, refer to Troubleshooting, "Inspecting Electrical Connectors".
Thoroughly inspect the following connectors and the wiring harnesses for the connectors:
Master ECM J2/P2 connectors
J13/P13 connectors