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| Illustration 1 | g01379213 |
Schematic of the speed sensor for the rear wheel drive | |
This diagnostic trouble code is associated with the speed sensor for the rear wheel drive. This diagnostic trouble code is recorded when the ECU reads the signal from the sensor and the ECU determines that the signal is erratic, intermittent, or incorrect.
The possible causes of this diagnostic trouble code are listed:
- Wire (X967-BR) is shorted to the ground circuit while the machine is in operation.
- Wire (X966-OR) is shorted to the +battery.
- An open circuit exists.
- The ECU has failed. This is unlikely.
Note: The following test procedure may create other diagnostic trouble codes. Ignore these created diagnostic trouble codes and clear the diagnostic trouble codes when the original diagnostic trouble code has been corrected. Ensure that the diagnostic trouble code of CID 2999 FMI 02 is active before performing this procedure.
Note: Use a digital multimeter for the measurements in this procedure.
Test Step 1. VERIFY THE SOFTWARE VERSION.
Note: From SIS or the latest release of the CD for SIS, check and record the latest software version for the machine electronic controls.
- Verify that the Transmission ECU has the most current version of software.
- Verify that the ECU has the latest version of software.
Expected Result:
All of the software is current.
Results:
- OK - All of the software is current. Proceed to Test Step 2.
- NOT OK - A recent version of software is available.
Repair: Flash all controls with the latest software release. Refer to Testing and Adjusting, "Electronic Control Unit - Flash Program".
STOP
Test Step 2. CHECK THE HARNESS.
- Turn the key start switch to the OFF position.
- Inspect the harness.
- Check for the proper mating.
- Check the exposed wires for nicks and abrasions.
- Check for moisture, dirt, or corrosion.
- Check the pin/socket for a proper fit.
- Disconnect the machine harness connectors from the Transmission ECU.
- At the machine harness connector, measure the resistance from connector contact J1-17 (wire X966-OR) and J1-18 (wire X967-BR) to all of the contacts in the J1 and J2 machine harness connectors.
Expected Result:
The resistance should be less than 5 ohms.
Results:
- OK - The resistance is less than 5 ohms. The machine harness is correct. Proceed to test step 3.
- NOT OK - The resistance is greater than 5 ohms. There is an open in the machine harness. The open is in wire X966-OR or in wire X967-BR.
Repair: Repair the machine harness or replace the machine harness.
STOP
Test Step 3. CHECK IF THE DIAGNOSTIC TROUBLE CODE IS STILL ACTIVE.
- Inspect the harness connectors. Clean the contacts of the harness connectors and check the wires for damage to the insulation that is caused by excessive heat, battery acid, or chafing.
- Perform a 45 N (10 lb) pull test on each of the wires that are associated with the circuit.
- Reconnect all harness connectors in order to make sure that the connectors are fully seated. Also, make sure that the clips for each connector are completely fastened.
- Turn the disconnect switch and the key start switch to the ON position.
- Operate the machine.
- Determine if the CID 2999 FMI 02 is active.
Expected Result:
The CID 2999 FMI 02 is active.
Results:
- YES - The CID 2999 FMI 02 is active. The problem has not been corrected.
Repair: It is unlikely that the ECU has failed. Exit this procedure and perform this procedure again. Prior to replacing an ECU, always contact your dealership for possible consultation with Caterpillar. This consultation may greatly reduce repair time. See Testing and Adjusting, "Electronic Control Unit - Replace".
STOP
- NO - The CID 2999 FMI 02 is not active. The problem does not exist at this time.
Repair: The initial diagnostic trouble code was probably caused by a poor electrical connection or a short at one of the harness connectors that was disconnected and reconnected. Resume normal machine operation.
STOP