CORNER 3908393 - Caterpillar

Turn the engine control to the OFF/RESET mode. Turn the engine battery disconnect switch to the OFF position.
Disconnect connector 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 requires at least 22 N (5 lb) of force in order to push in the sliphead from the extended position.Results:
OK - The sensor and the sliphead are undamaged. The tension on the sliphead is normal. Reinstall the sensor. Proceed to Test Step 4.
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".STOPTest Step 4. Check the Engine RPM on Cat ET
Turn the engine control to the STOP mode. Turn the engine battery disconnect switch to the ON position. Start the engine.
Observe the engine speed on Cat ET. Expected Result:Cat ET displays a steady engine speed between 100 and 250 rpm while the engine is cranking.Results:
OK - The Cat ET screen displays a steady engine speed between 100 and 250 rpm while the engine is cranking. 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 Cat ET screen does not display a steady engine speed between 100 and 250 rpm while the engine is cranking. The Cat ET screen does not display the correct engine rpm signal. Proceed to Test Step 5.Test Step 5. Check the Supply Voltage to the Sensor
Disconnect the engine speed/timing connector J20/P20.
Turn the engine control to the STOP mode. The engine should be off.
Measure the voltage at the connector for the engine speed/timing sensor between J20-A and J20-B. Expected Result:The supply voltage is 12.5 1.0 VDC.Results:
OK - The supply voltage is 12.5 1.0 VDC. The sensor is receiving the correct supply voltage. Proceed to Test Step 6.
Not OK - The supply voltage is not 12.5 1.0 VDC. The supply voltage is incorrect. Proceed to Test Step 8.Test Step 6. Check the Signal Voltage at the Sensor
Remove the signal wire 999-WH(White) from the sensor connector P20-C.
Reconnect connector J20/P20.
Turn the engine control to the STOP mode. Turn the engine battery disconnect switch to the ON position. The engine should be off.
Measure the voltage between the signal wire 999-WH(White) from the sensor connector P20-C and the engine ground.
Crank the engine. Measure the voltage between the signal wire 999-WH(White) from the sensor connector P20-C and the engine ground.
Turn the engine control to the OFF/RESET mode. Turn the engine battery disconnect switch to the OFF position.
Reinsert the sensor signal wire back into P20-C. Expected Result:The voltage measures less than 3 VDC or more than 9 VDC when the engine is not cranking. While the engine is cranking, the voltage is