SEAL-O-RING 8J8343 - Caterpillar

System Operation Description:When the local emergency stop switch on the instrument panel is depressed, the coil of relay "R4" is energized. Terminal 1 of "DIODE_1_2" is energized at the same time. Terminal 4 of "DIODE_1_2" will energize the coil of relay "R2A". When relay "R2A" is energized, power is removed from the engine's Electronic Control Module (ECM). The ECM will power down. The injection signals to the injector solenoids will stop. The emergency stop lamp on the instrument panel will illuminate.Terminal 4 of "DIODE_1_2" also supplies power to terminal 3 of the connector for the timer. When power is applied to terminal 3 of the connector for the timer, the timer will activate. The timer outputs 24 VDC to terminal 6 of the connector for the timer for 2.5 seconds. The 24 VDC from terminal 6 of the connector for the timer is applied to the coil of the air shutoff switch (ASOS). The contact of the "ASOS" energizes the air shutoff solenoids. The timer will output voltage to the coil of the "ASOS" for approximately 2.5 seconds. The "ASOS" will then deactivate removing power to the air shutoff solenoids. This prevents damage to the air shutoff solenoids. A normally open switch at the air shutoff valves will close when the air shutoff solenoid activates the air shutoff valve. The switch input to the ECM notifies the ECM that the air shutoff valves are closed. The ECM will not send injection signals to the injector solenoids until the switch inputs from the air shutoff valves indicate that the valves are open.Relay "R3A" and relay "R3" are energized at the same time as the "ASOS" through terminal 3 of "DIODE_1_2". Terminal 3 of "DIODE_1_2" will energize relay "R3A" and relay "R3" for 2.5 seconds. The relays "R3A" and "R3" will de-energize after 2.5 seconds. The overspeed indicator on the instrument panel will illuminate for 2.5 seconds.In order to start the engine after an emergency stop condition, the ECS must be turned to the OFF/RESET position. This resets the ECM and the air shutoff timer. In addition to turning the ECS to the OFF/RESET position, the operator must manually open the air shutoff valves before starting the engine.
Illustration 1 g01597037
Typical example
Illustration 2 g01322302
Terminal locations for the following connectors P-C1/A-C90 Connector for the power distribution panel, A-C2/J-C2 RH rigid harness connector and C-C2/J-C1 LH rigid harness connectors
(Terminal G) Drive for the air shutoff switch F708-BK(Black)
(Terminal H) Return for the air shutoff solenoid H708-BK(Black)
(Terminal I) Drive for the air shutoff solenoid G708-BK(Black)
Illustration 3 g01337991
Connector locations
(1) A-C1/E-C2 RH rigid harness connectors
(2) A-C2/J-C2 RH rigid harness connectors
(3) P-C1/A-C90 Connectors for the power distribution panel
(4) P-C2/A-C91 Connectors for the power distribution panel
(5) G-C6/F-C2/F-C1/A-C92 Connectors for a RH Control panel
(6) C-C22 Connection for the P2 ECM connector
(7) C-C15 Connection for the P1 ECM connector
(8) G-C6/F-C2/F-C1/C-C17 Connectors for a LH Control panel
(9) C-C18/TB-C1 Customer connectors
(10) C-C2/J-C1 LH rigid harness connectors
(11) C-C1/E-C1 LH rigid harness connectors Test Step 1. Inspect the Electrical Connectors and the Wiring
Verify that the circuit breakers are