TUBE AS 2185827 - Caterpillar

Illustration 3 g00823118
Relay terminals
Turn the keyswitch to the OFF/RESET position.
Unplug the start aid relay.
Measure the resistance between terminal 85 and terminal 86 of the relay.Expected Result:The resistance should be between 250 Ohms and 500 Ohms.Results:
OK - Proceed to Test Step 9.
Not OK - The relay is faulty.Repair: Replace the relay.Verify that the repair eliminates the problem.STOPTest Step 9. Check the Signal Voltage to the Relay
Illustration 4 g00823292
Relay connector (terminal side)Note: The ether canister must be removed prior to activating this test.
Unplug the start aid relay.
Turn the keyswitch to the ON position.
Proceed to the "Diagnostic Overrides" screen on ET.
Activate the ether injection system.Note: The diagnostic override will only activate the relay for 3 seconds.
Measure the voltage between terminal 85 (Solenoid Return) and terminal 86 (Ether ON) of the plug for the relay.Expected Result:The voltage should be 24.0 8.0 VDC.Results:
OK - The relay is receiving the signal from the ECM. Proceed to Test Step 10.
Not OK - The relay is not receiving the signal from the ECM. Proceed to Test Step 12.Test Step 10. Check the Output Voltage of the Relay
Illustration 5 g00822999
Relay connector (wire side)Note: The ether canister must be removed prior to activating this test.
Ensure that all connectors are connected to the wiring harness.
Turn the keyswitch to the ON position.
Proceed to the "Diagnostic Overrides" screen on ET.
Activate the ether injection system.Note: The diagnostic override will only activate the relay for 3 seconds.
Use signal reading probes to measure the voltage across terminal 85 (Solenoid Return) and terminal 87 (Solenoid Power) of the relay.Expected Result:The voltage should be 24.0 8.0 VDC.Results:
OK - There is a problem in the wiring between the relay and the start aid solenoid.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOP
Not OK - The relay is not sending power to the solenoid. Proceed to Test Step 11.Test Step 11. Check the Power Supply to the Relay
Illustration 6 g00823292
Relay connector (terminal side)
Unplug the start aid relay.
Measure the voltage between terminal 30 (+Battery) of the connector for the relay and chassis ground.Expected Result:The voltage should be 24.0 8.0 VDC.Results:
OK - The relay is faulty.Repair: Replace the relay.Verify that the repair eliminates the problem.STOP
Not OK - There is a problem in the wiring between the relay and the +Battery terminal.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOPTest Step 12. Check for Shorts in the Wiring Harness between the Relay and the ECM
Illustration 7 g00823185
ECM connector P1 (ECM side)
Ensure that the keyswitch is in the OFF/RESET position.
Disconnect the J1/P1 ECM connector.
Unplug the start aid relay.
Measure the resistance between P1:21 (Start Aid Relay) and P1:67 (Solenoid Return).Expected Result:The resistance should be greater than 20,000 Ohms.Results:
OK - Proceed to Test Step 13.
Not OK - There is a short between the ECM and the relay.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOPTest Step 13. Check the Voltage for the Relay at the ECM
Illustration 8 g00823285
ECM connector P1 (wire side)Note: The ether canister must be removed prior to activating this test.
Turn the keyswitch to the OFF/RESET position.
Remove the wire from P1:21 (Start