INSERT 4T1112 - Caterpillar

Illustration 1 g00530097
System Schematic For The Engine Speed SensorThe EMCP II+ system monitors engine speed. The EMCP II+ system uses engine speed in order to accomplish many tasks. These tasks are included in the following list.
Activating a shutdown for engine overspeed
Terminating engine cranking
Determining the oil step speed
Causing the air shutoff solenoid to engage during some fault shutdownsThe EMCP II+ does not control engine speed. The engine speed sensor is mounted on the flywheel housing of the engine.The sensor creates a sine wave signal. The signal is created from passing ring gear teeth. The rate of the signal is one pulse per tooth. The sensor sends the sine wave signal to the GSC+. The frequency of the signal is directly proportional to the speed of the engine.The GSC+ treats a CID 190 FMI 2 as a shutdown fault. The engine is not allowed to crank or the engine is not allowed to run when a CID 190 FMI 2 diagnostic code is active.Note: The Engine Speed Sensor is commonly referred to as magnetic pickup.Note: Engines that are equipped with an electronic governor or electronic engine control (PEEC) have a separate speed sensor. The cable of the speed sensor that is used by the GSC is marked with one of the following numbers: 838-873, 838-973 and 973-938This troubleshooting procedure is for a CID 190 FMI 2 that is active or inactive.The possible causes of a CID 190 FMI 2 are listed below.
The frequency of the signal is beyond accepted limits. There is a short to the battery negative terminal.
The air gap of the speed sensor is too large.Clear the diagnostic code from the fault log after troubleshooting is complete.Test Step 1. CHECK THE HARNESS AND THE SPEED SENSOR.
Turn the engine control switch (ECS) to OFF/RESET.
Disconnect the harness connector from the GSC+.
At the GSC+ harness connector, measure the resistance from contact "1" to contact "2".Expected Result:The resistance should be from 100 to 350 ohms.Results:
OK - There is probably an intermittent problem. Proceed to Test Step 2.
NOT OK - The harness wiring or the speed sensor has failed. Proceed to Test Step 3.Test Step 2. CHECK FOR AN INTERMITTENT FAULT.
Turn the ECS to OFF/RESET.
Turn the ECS to STOP.
Check the upper display for a CID 190 FMI 2.Expected Result:CID 190 FMI 2 should not appear on the upper display.Results:
OK - CID 190 does not appear on the upper display. This step has corrected the problem. Stop.
NOT OK - CID 190 FMI 2 appears on the upper display. Proceed to Test Step 3.Test Step 3. CHECK THE RESISTANCE OF THE ENGINE SPEED SENSOR.
Disconnect the sensor from the engine harness. The sensor remains fastened to the engine.
At the connector of the sensor, measure the resistance between contact "1" and contact "2".Expected Result:The resistance should be between 100 to 350 ohms.Results:
OK - The resistance of the sensor is correct. Proceed to Test Step 4.
NOT OK - Replace the sensor.Repair: Refer to Testing And Adjusting, "Speed Sensor (Engine) - Adjust". Stop.Test Step 4. CHECK THE HARNESS FOR