0387336 JOHNSON COVER ASSY. & BUSHING

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Circuit schematic for the warning lamp
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Pin locations for the warning lamp circuitTest Step 1. Inspect Electrical Connectors and Wiring
Thoroughly inspect ECM vehicle harness connector J1/P1, the firewall bulkhead connector, and terminal 29. Refer to Illustration 2. 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 that is associated with the suspect terminal for the lamp.
Check the ECM connector (allen head screw) for the proper torque of 6.0 N m (55 lb in).
Check the harness and wiring for abrasion and pinch points from the battery to the ECM.Expected Result:All connectors, pins and sockets should be completely coupled and/or inserted and the harness and wiring should be free of corrosion, abrasion or pinch points.Results:
OK - Proceed to Test Step 2.
Not OK - 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.STOPTest Step 2. Check for Normal Operation of the Warning Lamp
Monitor the warning lamp. Turn the ignition key switch to the ON position, while the engine is off. The lamp should turn on for five seconds. Then, the lamp should turn off.The lamp will continue flashing if there is an active diagnostic code. If there is an active diagnostic code, connect Caterpillar Electronic Technician (Cat ET) in order to read the active diagnostic code. Troubleshoot the problem.Note: The warning lamp will not turn on until the engine is cranked.
Connect Cat ET to the cab data link connector. Verify that the "Engine Monitoring" has been programmed to "", "DERATE", or "SHUTDOWN".While the warning lamp is being observed, start the engine. The warning lamp should turn on for a minimum of two seconds after the engine starts. Then, the warning lamp should turn off. If the lamp remains off, immediately shut down the engine.Expected Result:The warning lamp turns on and the warning lamp turns off per the above description.Results:
OK - The lamp appears to operating correctly at this time.STOP
Not OK - The lamp does not turn on. Proceed to Test Step 3.
Not OK - The lamp stays on.Repair: Perform the following diagnostic procedure:Use Cat ET to determine if an "Engine Monitoring" condition is causing the lamp to turn on. If an "Engine Monitoring" condition is not present, perform the following diagnostic procedure. Proceed to Test Step 3.Test Step 3. Test the Lamp Circuit
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Vehicle harness connector P1
Disconnect ECM vehicle harness connector J1/P1.
Fabricate a jumper wire 100 mm (4 inch) long. Crimp a Deutsch pin to both ends of the wire.
Insert the jumper intoP1:29 (warning lamp). The jumper can be inserted into the following terminals in order to test the appropriate lamp circuit:
Connect the other side of the jumper wire to P1:65 (-battery).
Turn the ignition key switch to the ON position.
While the lamp is being watched, insert the jumper wire and remove the jumper wire. Refer to Illustration 3.Expected Result:Result 1 The warning lamp turns on while the jumper is connected to both sockets. Also, the warning lamp turns off when the jumper is removed from one of the sockets.Result 2 The lamp does not turn on while the jumper is connected to both sockets.Result 3 The lamp will stay on while the ECM vehicle harness connector is disconnected.Results:
Result 1 - The warning lamp circuit is functioning properly. Proceed to Test Step 4.
Result 2 - The lamp did not turn on. The vehicle's lamp circuit is not functioning properly. The lamp is probably burned out or there is a problem in the wiring from the cab to either the ECM or the +battery connection. Repair the lamp circuit or send the vehicle to the OEM dealer for repairs.STOP
Result 3 - Repair: Perform the following diagnostic procedure:The circuit between the ECM and the lamp is shorted to chassis ground. Repair the circuit or send the vehicle to the OEM dealer for repairs.STOPTest Step 4. Check the Operation of the ECM Output for the Warning Lamp
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ECM breakout T-connector
Disconnect ECM vehicle harness connector J1/P1.
Insert a breakout T between the ECM vehicle harness connectors J1 and P1.
Connect a test light probe to terminal 65 (-battery) and connect the other probe to terminal 52 (unswitched +battery) of the breakout T.
The test lamp should turn on. If the test lamp does not turn on, either the test lamp is faulty or the wiring to the ECM is faulty. Continue with this step if the lamp turns on.
Leave the test light pro