PISTON GP 2744720 - Caterpillar

Illustration 1 g01022982
Typical circuit with "EMCP II"
Illustration 2 g01022983
Typical circuit with "EMS II"Test Step 1. Check for Connector Damage.
Turn the ECS to the OFF/RESET position.
Turn the battery disconnect switch to the OFF position.
Thoroughly inspect the ECM connectors J1/P1 and J2/P2. Inspect all of the other connectors. Refer to the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the circuit.
Check the ECM connector (allen head screw) for the proper torque of 6.0 N m (55 lb in).
Check the customer connector (allen head screw) for the proper torque of 2.25 0.25 N m (20 2 lb in).
Check the harness and the wiring for abrasion and for pinch points.Expected Result:All connectors, pins, and sockets are completely coupled and/or inserted, and the harness and wiring are free of corrosion, of abrasion or of pinch points.Results:
OK - The connectors and wiring are okay. Proceed to Test Step 2.
Not OK - The connectors and/or wiring are not okay.Repair: Repair the connectors and/or wiring or replace the connectors and/or wiring. Stop.Test Step 2. Check the Voltage to the Coil of the Air Shutoff Relay.
Connect a voltmeter between terminal 86 and terminal 85 on the air shutoff relay.
Turn the circuit breaker for the battery to the ON position.
Turn the ECS to the STOP position on engines with the "EMCP II+" panel. Turn the ECS to the SERVICE position on engines with the "EMS II" panel.
Fabricate a wire jumper. Connect one terminal of the wire jumper to +Battery. Momentarily connect the other terminal of the wire jumper to terminal 86 of the air shutoff relay.
Measure the voltage across the coil of the air shutoff relay.
Remove the wire jumper to terminal 86 of air shutoff relay.Expected Result:The voltage measures 24 3 VDC.Results:
OK - The voltage measures 24 3 VDC. Proceed to Test Step 3.
Not OK - The voltage does not measure 24 3 VDC.Repair: Check wire 2 for continuity between the air shutoff relay and the -Battery. If necessary, repair wire 2. If wire 2 is okay, replace the air shutoff relay. Stop.Test Step 3. Check the Voltage from the Contacts of the Air Shutoff Relay.
Connect a voltmeter from terminal 87 of the air shutoff relay and the -Battery terminal.
Turn the ECS to the STOP position on engines with the "EMCP II+" panel. Turn the ECS to the SERVICE position on engines with the "EMS II" panel.
Fabricate a wire jumper. Connect one terminal of the wire jumper to +Battery. Momentarily connect the other terminal of the wire jumper to terminal 86 of the air shutoff relay.
Measure the voltage from the contact of the air shutoff relay.
Remove the wire jumper to terminal 86 of air shutoff relay.Expected Result:The voltage measures 24 3 VDC.Results:
OK - The voltage measures 24 3 VDC. Proceed to Test Step 4.
Not OK - The voltage does not measure 24 3 VDC.Repair: Verify that 24 3 VDC is