ALTERNATOR GP-CHARGING 2253146 - Caterpillar

System Operation Description:The Electronic Control Module (ECM) contains the logic and the outputs for control of starting the engine and stopping the engine. The logic for starting and for stopping is customer programmable. The logic responds to inputs from the following components: engine control, emergency stop switch, remote start switch, data link and other inputs.To enable fuel flow to the engine, the fuel shutoff valve (GSOV) must be energized. The GSOV may be controlled by the ECM or by the customer's equipment. Use this procedure to troubleshoot either configuration.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 ECM.A 0017-12 diagnostic code is activated after the following sequence of events:
The engine is running.
The ECM receives a signal for stopping the engine.
The ECM removes power from the electrical circuit for the GSOV.
The engine rpm does not drop at least 100 rpm within the time that is specified by the "Engine Speed Drop Time" parameter.When these events occur, the ECM assumes that the GSOV did not close. The ECM terminates the ignition. The ECM also issues a 0017-12 diagnostic code. Unburned gas remains in the air inlet and exhaust system.The following information describes the system's operation when the GSOV is controlled by the ECM:The ECM output for the fuel shutoff valve is called the "fuel control relay". This output is energize-to-run. The ECM provides +Battery voltage to this output when the logic determines that fuel is required for engine operation. The ECM removes the voltage from this output in order to stop the engine. The fuel shutoff valve is de-energized. This stops the fuel flow.There are four configurations for the wiring when the fuel shutoff valve is controlled by the ECM. Refer to Illustration 1. Each configuration must be a closed loop that includes the GSOV. The customer may install an additional emergency stop button anywhere in the loop. The customer's optional additional buttons are not shown.The following information describes the system's operation when the GSOV is controlled by the customer's equipment:If the GSOV is controlled by the customer's equipment, the circuit for the ECM must be a complete path. The circuit must include a resistor. Refer to Illustration 2.
Illustration 1 g01091260
Schematics of the four options for the wiring for the fuel control relayIn these configurations, the fuel control relay is controlled by the ECM.
Illustration 2 g01091253
Schematic of the circuit for the fuel control relay when the relay is not controlled by the ECM.In this configuration, the circuit must include a resistor. A typical installation is shown.Test Step 1. Inspect the Electrical Connectors and Wiring
Illustration 3 g01087593
(1) J2/P2 connectors for the master ECM (2) J5/P5 connectors for the customer's connections (3) J8/P8 connectors for the harness from the fuel