0388933 JOHNSON FUEL CAP ASSY

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Schematic
The connection of any electrical equipment and the disconnection of any electrical equipment may cause an explosion hazard which may result in injury or death. Do not connect any electrical equipment or disconnect any electrical equipment in an explosive atmosphere.
Test Step 1. Test Communication of the Cat Data Link
Turn the keyswitch to the OFF position.
Connect Cat ET to the service tool connector.
Turn the keyswitch to the ON position.
Select the engine ECM from the "ECM Selector" screen on Cat ET.Results:
OK - Cat ET has established communications with the ECM. The Cat Data Link is functioning properly. Proceed to Test Step 2.
Not OK - Cat ET cannot establish communications with the ECM. The Cat Data Link is not functioning properly.Repair: Proceed to Troubleshooting, "Electronic Service Tool Will Not Communicate with ECM".STOPTest Step 2. Inspect the Electrical Connectors and the Wiring
Turn the keyswitch to the OFF position.
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Top view (1) J1/P1 ECM connectors (2) J3 Customer connector
Thoroughly inspect connectors (1) and (2). Inspect the harness and all of the other connectors that are in the wiring harness from the J3/P3 customer connector to the J42 service tool connector. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
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P1 ECM connector (P1-1) ATA Data Link (-) (P1-7) ATA Data Link (+)
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J42 Service tool connector (customer supplied) (J42-A) +Battery (J42-B) -Battery (J42-J) ATA Data Link (+) (J42-H) ATA Data Link (-)
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the ATA data link.
Check the allen head screw on the ECM connectors and the customer connector. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque value.
Check the wiring harnesses for abrasion, for corrosion, and for pinch points.Expected Result:All connectors, pins, and sockets are completely inserted, and coupled. The harness and wiring are free of corrosion, of abrasion, and of pinch points.Results:
OK - The harness and the wiring appear to be OK. Proceed to Test Step 3.
Not OK - There is a problem in the wiring harness.Repair: Repair the connectors and/or the wiring. Replace damaged parts, if necessary. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled. Verify that the problem is resolved.STOPTest Step 3. Check for a Short Circuit
Disconnect the J1/P1 ECM connector.
Measure the resistance between the points that are listed in Table 1. Be sure to wiggle the wires in the harnesses as you make each resistance measurement.
Table 1
Resistance Measurements for the ATA Data Link    
Connector and Terminal    Terminal    
P1-7 ATA data link +     All of the other terminals on the P1 connector
Engine ground    
P1-1 ATA data link -    
Expected Result:Each check of the resistance indicates an open circuit.Results:
OK - Each check of the resistance indicates an open circuit. Proceed to Test Step 4.
Not OK - At least one check of the resistance does not indicate an open circuit. There is a short circuit in a harness. There may be a problem with a connector.Repair: Repair the wiring and/or the connector. Replace damaged parts, if necessary. Verify that the problem is resolved.STOPTest Step 4. Check for an Open Circuit
Verify that all of the connections are disconnected.
Fabricate a jumper wire. Use the jumper wire in order to create a short circuit between terminals J42-J and J42-H on the service tool connector.
Measure the resistance between P1-7 ATA data link + and P1-1 ATA data link -.
Remove the jumper wire from the service tool connector.Expected Result:The resistance is less than ten Ohms.Results:
OK - The resistance is less than ten Ohms. There is not an open circuit. Restore the engine wiring to the original configuration. Proceed to Test Step 5.
Not OK - The resistance is more than ten Ohms. There is an open circuit or excessive resistance in the circuit. There may be a problem in a connector.Repair: Repair the wiring and/or the connector. Replace damaged parts, if necessary. Verify that the problem is resolved.STOPTest Step 5. Verify the Operation of the ECM
Turn the ignition key switch to the ON position. Ensure that Cat ET can communicate with the engine.
Try again to flash program the ECM with the latest flash file that is available.Expected Result:The ECM has been successfully programmed with the latest flash file.Results:
OK - The ATA Data Link is communicating correctly. There may be an intermittent problem.Repair: Check the wiring harness and the service equipment for an intermittent electrical problem.Refer toTroubleshooting, "Electrical Connectors - Inspect".STOP
Not OK - The circuit for the ATA Data Link is OK, but Cat ET will not flash program the ECM. The problem is in the service equipment or the ECM.Repair: Ensure that the service equipment and the cables are working properly. Ensure that the flash file is the correct part number for the ECM.Replace the personality module and/or the ECM. Refer to Troubleshooting, "Replacing the ECM".STOP