RENR5042-02 95 Troubleshooting Section i02289818 Air Shutoff System - Test B. Verify that the air shutoff valves are set to the Open position. SMCS Code: 1078-038 System Operation Description: The Electronic Control Module (ECM) has the ability to stop the engine by shutting off the inlet air supply in an emergency situation. The ECM activates a relay which energizes the air shutoff solenoid. The solenoid trips the air shutoff valve. There are two conditions which can cause the ECM to activate the air shutoff relay. The first condition occurs when the ECM detects an engine overspeed. The relay will be energized until the ECM detects an engine speed of 0 rpm.
The second condition occurs when a test of the air shutoff relay is made. The overspeed verify switch is activated. When the engine speed reaches 75 percent of the programmed overspeed setpoint, the ECM will activate the air shutoff relay. Again, this is used for testing purposes. The air shutoff valve must be manually reset to the OPEN position. g01121151 Illustration 20 Left side view (1) P61 customer connector (2) J1/P1 ECM connectors C. Thoroughly inspect connectors (1) and (2). Refer to Troubleshooting, “Electrical Connectors - Inspect”. g00743757 Illustration 19 Schematic for the air shutoff system Test Step 1. Inspect the Electrical Connectors and the Wiring A.
Turn the keyswitch to the OFF position.