BOLT 3830579 - Caterpillar

Illustration 1 g01027471
Typical exampleTest Step 1. Check for Connector Damage
Turn the Engine Control Switch (ECS) to the OFF/RESET position. The engine should be off.
Turn the circuit breaker for the battery to the OFF position.
Thoroughly inspect the ECM connectors J1/P1 and J2/P2. 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 ECM connectors (allen head screw) for the proper torque. Refer to Troubleshooting, "Inspecting Electrical Connectors".
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 okay. 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 for the primary ECM and for the secondary ECM.
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 Cat Data Link −
Cat Data Link + to −Battery terminal
Cat Data Link − to −Battery terminal
Cat Data Link + to +Battery terminal
Cat Data Link − to +Battery terminal
Cat Data Link + to engine ground
Cat Data Link − to engine groundExpected Result:The resistance is greater than 20,000 Ohms for each measurement.Results:
OK - The resistance is greater than 20,000 Ohms. Proceed to Test Step 3.
Not OK - The resistance is less than 20,000 Ohms. 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
Turn the ECS to the OFF/RESET position. The engine should be off.
Turn the circuit breaker for the battery to the OFF position.
Disconnect the ECM connectors for the primary ECM and for the secondary ECM.
Disconnect any module that is connected to the Cat Data Link.
Short the wires of the Cat Data Link together. Create the short at P1-9 and P1-8 of the primary 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 at the connectors for the primary ECM and the secondary ECM. 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 is less than five Ohms for each measurement.Results:
OK - The resistance is less than five Ohms for each measurement.Repair: The harness is okay. There could be a problem with a module or with the ECM. Connect