3C8474 CLEANER GP-AIR Caterpillar parts
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Alternative (cross code) number:
CA3C8474
3C-8474
3C8474
CA3C8474
3C-8474
3C8474
Weight: 3 pounds 1 kg.
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The engine speed sensor is located on top of the flywheel housing.
Illustration 1 g01185056
Schematic of the engine speed sensor
This diagnostic code is associated with the engine speed sensor. The FMI 08 means that the ECM has determined that the signal frequency or the signal pulse width is not within the expected range. The possible causes of this diagnostic code are listed below:
The sensor has failed.
Intermittent connections or poor connections
Mechanical devices are loose.
The ECM has failed. This is unlikely.Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear the diagnostic codes when the original diagnostic code has been corrected. Ensure that the diagnostic code of CID 0190 FMI 08 is active before performing this procedure. The engine must be running in order for the diagnostic code to be active.Note: Use the 146-4080 Digital Multimeter for the measurements in this procedure. Test Step 1. CHECK THE SENSOR.
Turn the disconnect switch and the key start switch to the ON position.
Ensure that the diagnostic code is active.
Disconnect the sensor from the machine harness. Expected Result:The diagnostic code is NO longer active.Results:
OK - The diagnostic code is NO longer active. The sensor has failed.Repair: Replace the sensor. Verify that the new sensor corrected this diagnostic code. The diagnostic code should NOT be active.STOP
NOT OK - The diagnostic code remains active. The sensor is not the cause of the diagnostic code. Proceed to Test Step 2.Test Step 2. CHECK FOR A SHORT IN THE HARNESS.
The sensor remains disconnected from the machine harness.
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the J1 and J2 machine harness connectors from the Transmission/Chassis ECM.
At the J1 machine harness connector for the ECM, measure the resistance between the signal plus contact J1-2 (wire L912-WH(White)) to all other J1 and J2 contacts. Measure the resistance between the signal minus contact J1-3 (wire L913-OR(Orange)) to all other J1 and J2 contacts. Expected Result: Each resistance measurement should be greater than 5000 ohms.Results:
OK - Each resistance measurement IS greater than 5000 ohms. The harness is correct. The ECM may have failed.Repair: It is unlikely that the ECM has failed. Exit this procedure and perform this diagnostic code procedure again. If the cause of the diagnostic code is not found, replace the transmission ECM. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace". STOP
NOT OK - The resistance that is measured is NOT greater than 5000 ohms for all measurements. The machine harness has failed.Repair: There is a short in the machine harness. The short is between the signal circuit (wire L912-WH(White)) and the circuit with the low resistance measurement or the short is between the signal circuit (wire L913-OR(Orange)) and the circuit with the low resistance measurement. Repair the machine harness or replace the machine harness.STOP
Illustration 1 g01185056
Schematic of the engine speed sensor
This diagnostic code is associated with the engine speed sensor. The FMI 08 means that the ECM has determined that the signal frequency or the signal pulse width is not within the expected range. The possible causes of this diagnostic code are listed below:
The sensor has failed.
Intermittent connections or poor connections
Mechanical devices are loose.
The ECM has failed. This is unlikely.Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear the diagnostic codes when the original diagnostic code has been corrected. Ensure that the diagnostic code of CID 0190 FMI 08 is active before performing this procedure. The engine must be running in order for the diagnostic code to be active.Note: Use the 146-4080 Digital Multimeter for the measurements in this procedure. Test Step 1. CHECK THE SENSOR.
Turn the disconnect switch and the key start switch to the ON position.
Ensure that the diagnostic code is active.
Disconnect the sensor from the machine harness. Expected Result:The diagnostic code is NO longer active.Results:
OK - The diagnostic code is NO longer active. The sensor has failed.Repair: Replace the sensor. Verify that the new sensor corrected this diagnostic code. The diagnostic code should NOT be active.STOP
NOT OK - The diagnostic code remains active. The sensor is not the cause of the diagnostic code. Proceed to Test Step 2.Test Step 2. CHECK FOR A SHORT IN THE HARNESS.
The sensor remains disconnected from the machine harness.
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the J1 and J2 machine harness connectors from the Transmission/Chassis ECM.
At the J1 machine harness connector for the ECM, measure the resistance between the signal plus contact J1-2 (wire L912-WH(White)) to all other J1 and J2 contacts. Measure the resistance between the signal minus contact J1-3 (wire L913-OR(Orange)) to all other J1 and J2 contacts. Expected Result: Each resistance measurement should be greater than 5000 ohms.Results:
OK - Each resistance measurement IS greater than 5000 ohms. The harness is correct. The ECM may have failed.Repair: It is unlikely that the ECM has failed. Exit this procedure and perform this diagnostic code procedure again. If the cause of the diagnostic code is not found, replace the transmission ECM. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace". STOP
NOT OK - The resistance that is measured is NOT greater than 5000 ohms for all measurements. The machine harness has failed.Repair: There is a short in the machine harness. The short is between the signal circuit (wire L912-WH(White)) and the circuit with the low resistance measurement or the short is between the signal circuit (wire L913-OR(Orange)) and the circuit with the low resistance measurement. Repair the machine harness or replace the machine harness.STOP