0436772 JOHNSON GEARCASE ASSY., Complete

Illustration 1 g01007022
Test Step 1. Test the EMS Display
Turn the keyswitch to the ON position.
Activate the EMS test switch.Expected Result:All of the lamps on the EMS display illuminate.Results:
OK - The EMS display is operating correctly. Proceed to Test Step 3.
Not OK - There is a problem with the EMS display. Proceed to Test Step 2.Test Step 2. Check the Power Supply to the EMS Display
Turn the keyswitch to the OFF position.
Disconnect the connector on the back of the EMS display.
Turn the keyswitch to the ON position.
Measure the voltage between terminal 1 (+Battery) and terminal 2 (-Battery) on the connector for the EMS display.Expected Result:The supply voltage to the EMS display is between 19 VDC and 27 VDC.Results:
OK - The supply voltage to the EMS display is OK.Repair: Continue to troubleshoot the EMS display.If the EMS display is faulty, replace the EMS display.Verify that the repair eliminates the problem. Stop.
Not OK - The supply voltage to the EMS display is not within the range.Repair: Repair the wiring for the power supply to the EMS display.Verify that the repair eliminates the problem. Stop.Test Step 3. Inspect Electrical Connectors and Wiring
Turn the keyswitch to the OFF position.
Thoroughly inspect the J2/P2 ECM connector and the J3/P3 machine connector. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector and the J3/P3 machine connector that are associated with circuits for the EMS display.
Check the ECM connector (allen head screw) for the proper torque of 2.25 N m (20 lb in).
Check the harness and wiring for abrasions and for pinch points from the EMS display to the ECM.Expected Result:All connectors, pins, and sockets are completely coupled and/or inserted. The harness and wiring are free of corrosion, of abrasion, and of pinch points.Results:
OK - Proceed to Test Step 4.
Not OK - Repair: Perform the following repair:Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.Verify that the repair eliminates the problem. Stop.Test Step 4. Check the Individual Circuits
Connect the Caterpillar Electronic Technician (Cat ET) to the service tool connector.
Turn the keyswitch to the ON position.
Access the "Override Parameters" in the "Diagnostic Tests" under the "Diagnostics" menu.
Select the circuit that needs to be tested and press the "Change" button.
Select "Ground" in order to turn off the lamp.
Select "Off" in order to turn on the lamp.Expected Result:The lamp on the EMS display changed accordingly.Results:
OK - The circuits for the EMS display are working correctly.Repair: If an intermittent problem is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect".Verify that the lamp was not on due to an abnormal operating condition. If an abnormal operating condition caused the lamp to turn on, troubleshoot the cause of the abnormal condition. Stop.
Always ON - There is an open in the circuit. Proceed to Test Step 5.
Always OFF - The circuit is shorted to ground. Proceed to Test Step 7.Test Step 5. Check for Open Circuits at the ECM
Turn the keyswitch to the OFF position.
Insert a 7X-1715 Adapter Cable (Forty-Pin Breakout) and a 134-5195 Adapter Cable between the J1 and P1 ECM connectors.
Turn the keyswitch to the ON position.
Use a jumper wire to short the suspect circuit to terminal 5 (-Battery) of the breakout T.Expected Result:The lamp turns off.Results:
OK - There may be a problem with the ECM.Repair: Temporarily connect a test ECM.If the test ECM fixes the problem, reconnect the suspect ECM.If the problem returns, permanently replace the ECM.Verify that the repair eliminates the problem. Stop.
Not OK - The ECM is OK.Repair: Remove the breakout T and reconnect the J1/P1 ECM connectors. Proceed to Test Step 6.Test Step 6. Check for Open Circuits at the J3/P3 Machine Connector
Turn the keyswitch to the OFF position.
Remove the wire for the suspect circuit from the P3 machine connector.
Turn the keyswitch to the ON position.
Short the wire to chassis ground.Expected Result:The lamp turns off.Results:
OK - There is a problem in the harness between the J3/P3 machine connector and the ECM.Repair: Inspect the wiring between the machine connector and the ECM.Repair the wiring or replace the wiring.Verify that the repair eliminates the problem. Stop.
Not OK - There is a problem in the harness between the J3/P3 machine connector and the EMS display.Repair: Inspect the wiring between the machine connector and the EMS display.Repair the wiring or replace the wiring.Verify that the repair eliminates the problem. Stop.Test Step 7. Check for Short Circuits at the ECM
Turn the keyswitch to the OFF position.
Remove the wire for the suspect circuit from the P1 ECM connector.
Turn the keyswitch to the ON position.Expected Result:The suspect lamp turns on.Results:
OK - There may be a problem with the ECM.Repair: Temporarily connect a test ECM.If the test ECM fixes the problem, reconnect the suspect ECM.If the problem returns, permanently replace the ECM.Verify that the repair eliminates the problem. Stop.
Not OK - The ECM is working properly. Proceed to Test Step 8.Test Step 8. Check for Short Circuits at the J3/P3 Machine Connector
Turn the keyswitch to the OFF position.
Remove the wire for the suspect circuit from the P3 machine connector.
Turn the keyswitch to the ON position.Expected Result:The suspect lamp turns on.Results:
OK - There is a problem with the harness between the J3/P3 machine connector and the ECM.Repair: Inspect the wiring between the machine connector and the ECM.Repair the wiring or replace the wiring.Verify that the repair eliminates the problem. Stop.
Not OK - There is a problem with the harness between the J3/P3 machine connector and the EMS display.Repair: Inspect the wiring between the machine connector and the EMS display.Repair the wiring or replace the wiring.Verify that the repair eliminates the problem. Stop.