DIFFERENTIAL AR 3168469 - Caterpillar

Be sure to extend the sliphead before you install the Engine Speed/Timing Sensor. Also check that the engine timing gear is in a position that will not allow the sliphead of the Engine Speed/Timing Sensor to protrude into one of the slots of the engine timing gear. This is done visually with a flashlight prior to the installation of the Engine Speed/Timing Sensor. Turn the crankshaft to rotate the engine timing gear, if necessary, to position the gear in a place that will not allow the sliphead to protrude into a slot. If the sensor sliphead does protrude into one of the slots, the sliphead will be broken off as the gear begins to rotate.
Turn the keyswitch to the OFF position.
Turn the breaker for the engine to the OFF position.
Disconnect J20/P20 and remove the Engine Speed/Timing Sensor.
Inspect the plastic sliphead for damage.
Check the tension. Gently extend the sliphead 3.5 mm (0.14 inch). Return the sliphead to the original position.
Extend the sliphead.
Install the Engine Speed/Timing Sensor.Expected Result:The sliphead should take at least 22 N (5 lb) of force to push in the sliphead from the extended position.Results:
OK - The Engine Speed/Timing Sensor and the sliphead are undamaged. The tension on the sliphead is normal. Reinstall the sensor. Proceed to test step 6.
Not OK - The Engine Speed/Timing Sensor or the sliphead is damaged and/or the sliphead has insufficient tension.Repair: Replace the Engine Speed/Timing Sensor. Calibrate the sensor. Perform the calibration procedure Troubleshooting, "Engine Speed/Timing Sensor - Calibrate". Stop.Test Step 5. Check the Resistance through the Harness.
Use a suitable piece of wire to short J20-A (996-GN) to J20-B (998-BR).
Measure the resistance from P1-32 (996-GN) and P1-29 (998-BR).
Use a suitable piece of wire to short J20-A (996-GN) to J20-C (999-WH).
Measure the resistance between P1-32 (996-GN) and P1-38 (999-WH).
Remove all shorts and reconnect J1/P1 and J20/P20.Expected Result:The resistance should be less than 10 Ohms through the wires.Results:
OK - The resistance is less than 10 Ohms. Proceed to test step 6.
Not OK - The resistance is greater than 10 Ohms. There is an open circuit or excessive resistance in the harness or connectors.Repair: Repair the connectors and/or wiring or replace the connectors and/or wiring. Stop.Test Step 6. Check the Engine RPM on the Cat ET.
Connect the Cat ET to the service tool connector J42.
Turn the breaker for the engine to the ON position.
Turn the keyswitch to the ON position. Crank the engine. Start the engine, when possible.
Observe the display on the Cat ET screen.
Turn the keyswitch to the OFF position.Expected Result:The Cat ET screen should display a steady engine speed between 100 and 250 rpm while the engine is cranking.Results:
OK - The engine speed is between 100 and 250 rpm. The Engine Speed/Timing Sensor is operating normally at this time.Repair: There may be an intermittent problem. If the problem is intermittent, perform the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors". Stop.
Not OK - The engine speed is not between 100 and 250 rpm while the engine is cranking. The Engine Speed/Timing Sensor is