This diagnostic code is for the sensor supply of the transmission oil temperature sensor or the steering oil temperature sensor.Both sensors are never present on the same machine. Refer to the Electrical System Schematic for the machine that is being serviced in order to determine the sensor that is on the machine.
This diagnostic code is recorded when the ECM reads the voltage of the sensor supply circuit (R800-OR) as above normal range. The transmission oil temperature sensor or the steering oil temperature sensor will not operate. The transmission may not shift smoothly when the transmission oil is cold (medium trucks). The top brake pressure will be reduced. The pressure is closer to the pressure that is used for the calibration of the brakes. The brakes may drag lightly.
The possible causes of this diagnostic code are listed below:
- The supply circuit (R800-OR) to the sensor is shorted to ground.
- The sensor has failed.
- The ECM has failed. This is unlikely.
Ensure that the CID 0269 FMI 04 is on hold and that the diagnostic code indicator shows "SERV CODE". This procedure can cause a CID 0177 FMI 03. Ignore these created problems. When the procedure is completed, clear the created problems.
Test Step 1. CHECK THE SENSOR.
- Turn the key start switch to the ON position.
- Access Service Mode. Place CID 0269 FMI 04 on hold. Ensure that the diagnostic code indicator shows "SERV CODE". See Testing and Adjusting, "Using the Caterpillar Electronic Technician to Determine Diagnostic Codes".
- While you observe the status of the diagnostic code indicator or you listen for the sounding of the action alarm, disconnect the machine harness from the sensor.
Expected Result:
If the sensor is not the cause of the problem, "SERV CODE" remains ON. If the sensor has failed, "SERV CODE" goes OFF.
Results:
- OK - "SERV CODE" remains ON. The sensor has not failed. The machine harness or the ECM may have failed. Proceed to Test Step 2.
- NOT OK - "SERV CODE" goes OFF.
Repair: The machine harness and the ECM are operating properly. The sensor has failed. Replace the sensor.
STOP
Test Step 2. CHECK THE SUPPLY CIRCUIT FOR A SHORT TO GROUND.
- The sensor remains disconnected from the machine harness.
- Turn the key start switch to the OFF position.
- Disconnect the machine harness connectors J1 and J2 from the ECM.
- At machine harness connector J2, measure the resistance from contact J1-44 ( sensor supply) to all possible sources of ground.
Expected Result:
Each resistance should be greater than 5000 ohms.
Results:
- OK - Each resistance is greater than 5000 ohms. The machine harness is correct. Proceed to Test Step 3.
- NOT OK - Each resistance is not greater than 5000 ohms.
Repair: There is a short in the machine harness. The short is between J1-44 (R800-OR) and a ground source.
STOP
Test Step 3. CHECK IF THE DIAGNOSTIC CODE IS STILL ACTIVE.
- Clean the contacts of the harness connectors.
- Reconnect all harness connectors.
- Turn the key start switch to the ON position.
- Enter service mode of the Caterpillar Monitoring System and clear all inactive diagnostic codes.
- Operate the machine.
- Determine if CID 0269 FMI 04 is present.
Expected Result:
The CID 0269 FMI 04 is active.
Results:
- YES - The CID 0269 FMI 04 is active. The problem has not been corrected.
Repair: Check the circuit again. If the Caterpillar Electronic Technician (ET) is available, use the Cat ET service tool in order to perform a "Wiggle Test" on the machine wiring harness. The "Wiggle Test" can detect shorts and opens in the machine wiring harness that are momentary or intermittent. It is unlikely that the ECM has failed. Exit this procedure and perform this procedure again. If the cause of the diagnostic code is not found, replace the ECM. Prior to replacing an ECM, always contact your dealership for possible consultation with Caterpillar. This consultation may greatly reduce repair time. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace".
STOP
- NO - CID 0269 FMI 04 is not present.
Repair: The initial diagnostic 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