5036800 JOHNSON HEAD ASSY, CYLINDER - PORT

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Typical schematic
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P1 ECM connector (P1-8) Cat Data Link + (P1-9) Cat Data Link −
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Service tool connector (Terminal D) Cat Data Link + (Terminal E) Cat Data Link −
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Location of ECM connectorsTest Step 1. Inspect Electrical Connectors and Wiring
Turn the local/remote switch on the control panel to the OFF/RESET position.
Thoroughly inspect the ECM connectors J1/P1. 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 allen head screw on each ECM connector for the proper torque. Refer to Troubleshooting, "Inspecting Electrical Connectors" for the correct torque values.
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, and of pinch points.Results:
OK - The connectors and wiring are OK. Proceed to Test Step 2.
Not OK - The connectors and/or wiring need repair.Repair: Repair the connectors and/or wiring or replace the connectors and/or wiring.STOPTest Step 2. Check for Electrical Shorts in the Harness
Disconnect the ECM connectors.
Disconnect any module that is connected to the Cat Data Link.
Measure the resistance at the following points. Wiggle the harness during the measurement in order to reveal an intermittent short.
Cat Data Link + to every terminal on ECM connector P1
Cat Data Link − to every terminal on ECM connector P1
Cat Data Link + to engine ground
Cat Data Link − to engine groundExpected Result:The resistance measurements indicate an open circuit.Results:
OK - The resistance measurements indicate an open circuit. Proceed to Test Step 3.
Not OK - The resistance does not indicate an open circuit. There is a short in the harness or in the connectors.Repair: Repair the connector and/or wiring or replace the connector and/or wiring.STOPTest Step 3. Check the Resistance through the Harness for an Open Circuit
Short the wires of the Cat Data Link together. Create the short at P1-9 and P1-8 of the ECM connector.
Set an ohmmeter on the 200 Ohm scale. Measure the resistance between the terminals of the Cat Data Link + and the Cat Data Link −. Measure the resistance between the terminals of any module that was connected to the Cat Data Link. Wiggle the harness during the measurements in order to reveal an intermittent open condition.
Reconnect all connectors and modules.Expected Result:The resistance measurements indicate a short circuit.Results:
OK - The resistance measurements indicate a short circuit.Repair: The harness is OK. There could be a problem with a module or with the ECM. Connect the suspect module on another engine. If the problem returns on the other engine, replace the suspect module. Turn the keyswitch to the OFF position. Turn the keyswitch to the STOP position. If the diagnostic code is still present, replace the ECM. Refer to the diagnostic procedure Troubleshooting, "Replacing the ECM".STOP
Not OK - The resistance measurements do not indicate a short circuit.Repair: There is an open circuit or there is excessive resistance in the harness. Repair the connectors and/or wiring or replace the connectors and/or wiring.STOP