HORN AS 6S7339 - Caterpillar

Illustration 1 g01945403
Connections of the 5 volt sensor supplyThe 5 volt power supply provides power to the oil level sensor for the transmission.The FMI 03 is recorded when the ECU reads the voltage of the sensor supply circuit as higher than the normal voltage.The following is a list of possible causes for this diagnostic trouble code:
The sensor supply circuit is shorted to the +battery circuit.
The return circuit is open in the machine harness.
A sensor has failed.
The ECU has failed. This is unlikely.Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear these diagnostic codes when the original diagnostic code has been corrected. Ensure that the diagnostic code of CID 0262 FMI 03 is active before performing this procedure.Note: Use a digital multimeter for the measurements in this procedure.Test Step 1. CHECK THE VOLTAGE AT THE SENSOR
Turn the disconnect switch and the key start switch to the ON position.
Disconnect the machine harness connector from the sensor.
At the machine harness connector for the sensor, measure the voltage from connector contact 1 (wire 709-OR) to connector contact 2 (wire 202-BK). Measure the voltage from connector contact 1 (wire 709-OR) to frame ground.Expected Result:Both voltage measurements are 5.0 0.5 VDC.Results:
OK - Both voltage measurements are 5.0 0.5 VDC. The voltage is correct. Proceed to Test Step 3.
NOT OK - The voltage measurement from connector contact 1 (wire 709-OR) to the frame ground is 5.0 0.5 VDC. However, the voltage measurement from connector contact 1 to connector contact 2 is not 5.0 0.5 VDC. The return circuit is faulty in the machine harness.Repair: The return circuit is faulty in the machine harness. Refer