COIL GP-EVAPORATOR & HEATER 2781440 - Caterpillar

Illustration 1 g01362225
Connections of the transmission output speed sensor 1This diagnostic code is associated with the transmission output speed sensor 1. The FMI 12 means that the ECM has determined that the signal frequency or the signal pulse width is not within the expected range.System Response:A diagnostic code will be displayed on the Caterpillar Electronic Technician (Cat ET). The tractor will operate normally unless more than one speed sensor has failed.Test Step 1. CHECK THE RESISTANCE OF THE CASE OF THE SENSOR .
Turn the key start switch and the disconnect switch (if equipped) to the OFF position.
Disconnect the machine harness connector from the sensor.
Measure the resistance from contact 1 and from contact 2 to the case of the sensor.Expected Result:The resistance is greater than 5000 ohms. Results:
OK - The resistance is greater than 5000 ohms. Proceed to Test Step 2.
NOT OK - The resistance is NOT greater than 5000 ohms. The speed sensor has failed.Repair: Replace the sensor.STOPTest Step 2. CHECK THE RESISTANCE OF THE SENSOR.
The key start switch and the disconnect switch (if equipped) remain in the OFF position.
Measure the resistance between contact 1 and contact 2 of the connector of the sensor.Expected Result:The resistance is between 600 and 1800 ohms.Results:
OK - The resistance is between 600 and 1800 ohms. The resistance is correct. Proceed to Test Step 3.
NOT OK - The resistance is NOT between 600 and 1800 ohms. The resistance is not correct. The sensor has failed.Repair: Replace the sensor.STOPTest Step 3. CHECK FOR AN OPEN HARNESS.
The key start switch and the disconnect switch (if equipped) remain in the OFF position.
Reconnect the machine harness connector to the sensor.
Disconnect the machine harness connectors J1 and J2 from the machine ECM.
At the machine harness connector J1, measure the resistance from contact J1-41 to J1-40.Expected Result:The resistance is between 600 and 1800 ohms.Results:
OK - The resistance is between 600 and 1800 ohms. The circuit is correct. Proceed to Test Step 4.
NOT OK - The resistance is NOT between 600 and 1800 ohms. The circuit is open in the machine harness. Repair: Repair the machine harness or replace the machine harness.STOPTest Step 4. CHECK FOR A SHORT IN THE RETURN CIRCUIT OF THE MACHINE HARNESS.
The key start switch and the disconnect switch (if equipped) remain in the OFF position.
Disconnect the machine harness from the sensor.
At the machine harness connector J1, measure the resistance between contacts J1-40 and J1-41 to all sources of ground.Expected Result:Each resistance measurement is greater than 5000 ohms.Results:
OK - Each resistance measurement is greater than 5000 ohms. Proceed to Test Step5.
NOT OK - There is a short in the machine harness.Repair: Repair the machine harness or replace the machine harness.STOPTest Step 5. INSPECT THE SENSOR AND ADJUST THE SENSOR.
The key start switch and the disconnect switch (if equipped) remain in the OFF position. The sensor remains disconnected from the machine harness.
Remove the speed sensor. Inspect the sensor for damage or the presence of foreign material on the tip. Expected Result:The sensor is free of foreign material and