0338921 JOHNSON SCREW, Extension, M8

Illustration 1 g00782111
Typical schematic
Test Step 1. Check for Connector Damage.
Turn the keyswitch to the OFF position.
Turn the battery disconnect switch to the OFF position.
Thoroughly inspect the Master 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 Master ECM connector that are associated with the circuit.
Check the Master ECM connector (allen head screw) for the proper torque of 2.25 0.25 N m (20 2 lb in).
Check the customer connector (allen head screw) for the proper torque of 2.25 0.25 N m (20 2 lb in).
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. The harness and wiring should be free of corrosion, of abrasion or of pinch points.Results:
OK - The connectors and wiring are okay. Proceed to Test Step 2.
Not OK - The connectors and/or wiring are not okay.Repair: Repair the connectors and/or wiring or replace the connectors and/or wiring.STOPTest Step 2. Check the Throttle Position on the Caterpillar Electronic Technician (ET).
Connect the Cat ET to the service tool connector.
Turn the keyswitch to the ON position. The engine should be OFF.
Observe the throttle position status on the Cat ET. Depress the throttle fully and release the throttle. Expected Result:The throttle position should read 0 percent when the throttle pedal is released. The throttle position should progressively increase to 100 percent when the throttle pedal is fully depressed.Results:
OK - The Throttle Position Sensor is operating correctly.Repair: The problem may be intermittent. If the problem is intermittent, perform the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors".STOP
Not OK - The Master ECM is not receiving a correct signal from the sensor. There may be a problem in the throttle assembly. Proceed to Test Step 3.Test Step 3. Inspect the Throttle Assembly.
Turn the keyswitch to the OFF position.
Inspect the throttle assembly for the following problems: loose components, bent components, broken components, missing components and worn components. Expected Result:The throttle assembly should operate smoothly without excessive drag. The throttle assembly should return to the low idle position in less than one second.Results:
OK - The throttle assembly functions properly. Proceed to Test Step 4.
Not OK - The throttle assembly does not operate smoothly.Repair: Repair the throttle assembly to proper working order. If necessary, replace the throttle assembly.STOPTest Step 4. Check the Digital Sensor Supply Voltage at the Sensor Connector.
Disconnect the throttle sensor connector J35/P35. Note: If you disconnect the sensor common from the Master ECM, an open circuit diagnostic code will be generated for the sensor. If you disconnect the sensor supply from the Master ECM, an open circuit diagnostic code will be generated for the sensor. Troubleshoot the original code. Delete the logged diagnostic codes when you are finished.
Turn the keyswitch to the ON position. The engine should be OFF.
Measure the voltage between the digital supply P35-A (X800-OR(Orange)) and the digital return P35-B (X998-BR(Brown)). Expected Result:The supply voltage should be 8 0.4 VDC.Results:
OK - The supply voltage is reaching the sensor. Proceed to Test Step 5.
Not OK - The supply voltage is not present at the sensor connector. Proceed to Test Step 8.Test Step 5. Check the Signal at the Sensor Connector.
Remove the wire J35-C (X912-GN(Green)) from the sensor connector J35/P35.
Reconnect connector J35/P35.
Turn the keyswitch to the ON position. The engine should be OFF.
Measure the frequency and the duty cycle between wire (X912-GN(Green)) and pin J35-B (X998-BR(Brown)). Depress the throttle and release the throttle while measuring the frequency and the duty cycle.
Reconnect all wires. Expected Result:The FREQUENCY should be between 483 and 654 Hz. The DUTY CYCLE measurements should be between 10 and 22 percent when the throttle is at the low idle position. The DUTY CYCLE measurements should be between 75 to 90 percent when the throttle is fully depressed.Results:
OK - A valid signal appears at the sensor connector. Proceed to Test Step 6.
Not OK - The signal at the sensor connector is incorrect.Repair: Temporarily connect a new sensor. Verify that the new sensor solves the problem before permanently installing the new sensor.STOPTest Step 6. Check the Signal at the Master