F177917 Force STARTER RELAY

Illustration 1 g00889743
Schematic for ether injection
Breathing ether vapors or repeated contact of ether with skin can cause personal injury. Personal injury may occur from failure to adhere to the following procedures.Use ether only in well ventilated areas.Do not smoke while changing ether cylinders.Use ether with care to avoid fires.Do not store replacement ether cylinders in living areas or in the operator's compartment.Do not store ether cylinders in direct sunlight or at temperatures above 49 °C (120 °F).Discard cylinders in a safe place. Do not puncture or burn cylinders.Keep ether cylinders out of the reach of unauthorized personnel.To avoid possible injury, be sure the brakes are applied and all controls are in Hold or Neutral when starting the engine.
Test Step 1. Inspect Electrical Connectors and Wiring
Turn the keyswitch to the OFF/RESET position.
Thoroughly inspect ECM connector J1/P1, machine connector J3/P3, and all other connectors in the wiring harness. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Inspect the following components for damage, corrosion, and incorrect attachment:
battery posts
alternator
breaker
engine ground
machine groundExpected Result:All connectors, pins, and sockets should be completely inserted and coupled. The harness and wiring should be free of corrosion, abrasion, and pinch points. All connections and grounds should be tight and free of corrosion.Results:
OK - Proceed to Test Step 2.
Not OK - Repair: Repair the circuit.Verify that the repair eliminates the problem. Stop.Test Step 2. Check the Starting Aid Switch Status on the Caterpillar Electronic Technician (Cat ET)
Remove the ether canister from the starting aid solenoid.
Connect Cat ET to the service tool connector.
Turn the keyswitch to the ON position.
Press the starting aid switch to "MANUAL". Observe the "Starting Aid Switch Status" on Cat ET.Expected Result:When the starting aid switch is pressed, Cat ET should display the status of the starting aid switch as ON.When the starting aid switch is not pressed, Cat ET should display the status of the starting aid switch as OFF.Results:
OK - The starting aid switch is operating correctly. Proceed to Test Step 6.
Not OK - The ECM is not properly reading the signal from the starting aid switch. Proceed to Test Step 3.Test Step 3. Check the Resistance of the Relay
Illustration 2 g00794643
Connector for the starting aid relay
Turn the keyswitch to the OFF/RESET position.
Measure the resistance across terminal 85 (solenoid return) and terminal 86 (Ether On).Expected Result:The resistance should be between 250 Ohms and 500 Ohms.Results:
OK - Proceed to Test Step 4.
Not OK - The relay is faulty.Repair: Replace the relay.Verify that the repair eliminates the problem. Stop.Test Step 4. Short the Switch Wires
Remove wire R974-OR (Starting Aid Switch) and wire L901-GY (Digital Return) from the starting aid switch.
Short wire R974-OR (Starting Aid Switch) to wire L901-GY (Digital Return).Expected Result:When the wires are shorted, Cat ET should display the status of the starting aid switch as ON.When the wires are not shorted, Cat ET should display the status of the starting aid switch as OFF.Results:
OK - The starting aid switch is not operating correctly.Repair: Replace the starting aid switch.Verify that the repair eliminates the problem. Stop.
Not OK - The starting aid switch is operating correctly. Proceed to Test Step 5.Test Step 5. Short the Switch Inputs at the ECM
Illustration 3 g00794674
ECM connector P1 (wire side)
Turn the keyswitch to the OFF position.
Remove the wire from terminals P1:22 (Starting Aid Switch) and P1:18 (Digital Return).
Turn the keyswitch to the ON position.
Observe the status of "Ether Switch" on Cat ET.
Turn the keyswitch to the OFF/RESET position.
Make a jumper wire with a Deutsch pin at each end of the wire.
Install the jumper wire between P1:22 (Starting Aid Switch) and P1:18 (Digital Return).
Turn the keyswitch to the ON position.
Observe the status of "Ether Switch" on Cat ET.
Remove the jumper and reinstall the wires in the P1 connector.Expected Result:When the wires are shorted, Cat ET should display the status of the starting aid switch as "ON".When the wires are not shorted, Cat ET should display the status of the starting aid switch as "OFF".Results:
OK - There is a problem in the wiring between the switch and the ECM.Repair: Repair the circuit.Verify that the repair eliminates the problem. Stop.
Not OK - The ECM is not reading the switch input properly.Repair: Verify your results. Replace the ECM. Refer to Troubleshooting, "Replacing the ECM" before replacing the ECM.Verify that the repair eliminates the problem. Stop.Test Step 6. Check the Resistance of the Starting Aid Solenoid
Disconnect connector J504/P504 (Starting Aid Solenoid connector).
Measure the resistance between J504:1 (Solenoid Power) and J504:2 (Solenoid Return).Expected Result:Resistance should be less than 10 Ohms.Results:
OK - Proceed to Test Step 7.
Not OK - The starting aid solenoid is faulty.Repair: Replace the ether solenoid.Verify that the repair eliminates the problem. Stop.Test Step 7. Check the Supply Voltage to The Starting Aid SolenoidNote: The ether canister must be removed prior to activating this test.
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