FRAME AS-ROLLER-LH 9W9539 - Caterpillar

Illustration 1 g02551058
Schematic of the Ambient Air Temperature SensorNote: The sensor does not connect directly to frame ground. The sensor connects to the return circuit of the Transmission ECM. The ECM connects the return wire to the frame ground internally.This diagnostic code is associated with the "Ambient Air Temperature" Sensor. This diagnostic code is recorded when the Transmission ECM reads the sensor signal as being above normal. There is a short to the sensor power supply.The possible causes of this diagnostic code are listed below:
The sensor power supply (wire K983-BU) from the electrical system to the sensor is open.
The return circuit (wire J842-BK) is open.
The signal circuit (wire C453-YL) is open or the sensor is disconnected.
The sensor has failed.
The ECM has failed. This failure is unlikely. Note: Ensure that the CID 0171 FMI 03 diagnostic code is on hold.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.Test Step 1. CHECK THE VOLTAGE AT THE SENSOR.
Turn the disconnect switch and the key start switch to the ON position.
Disconnect the sensor from the machine harness.
At the machine harness connector for the sensor, measure the voltage between contact 1 (wire K983-BU) and contact 2 (wire J842-BK).Expected Result:The voltage measurement should be 8 VDC 0.4VDC.Results:
OK - The voltage is 8 VDC 0.4 VDC. Proceed to Test Step 4.
NOT OK - The voltage measurement is NOT 8 VDC 0.4 VDC. Repair: There is an open in the machine harness or the ECM has failed. Failure of the Transmission ECM is unlikely. Proceed to Test Step 2.Test Step 2. CHECK FOR AN OPEN IN THE SUPPLY CIRCUIT.
The key start switch and the disconnect switch remain in the ON position.
The sensor remains disconnected from the machine harness.
At the machine harness connector for the sensor, measure the voltage from contact 1 (wire K983-BU) to ground.Expected Result:The voltage measurement should be 8 VDC 0.4 VDC.Results:
OK - The voltage measurement is 8 VDC 0.4 VDC. Proceed to Test Step 3.
NOT OK - The voltage measurement is NOT correct.Repair: The supply circuit is not correct. Repair the circuit or replace the circuit.STOPTest Step 3. CHECK FOR AN OPEN IN THE RETURN CIRCUIT.
Turn the key start switch and the disconnect switch to the OFF position.
The sensor remains disconnected from the machine harness.
Disconnect the machine harness connector J1 from the ECM.
At the machine harness connector for the sensor, install a jumper wire from contact 2 (wire J842-BK) to ground.
At the machine harness connector for the ECM, measure the resistance from contact J1-45 (wire J842-BK) to ground.Expected Result:The resistance measurement should measure less than 5 ohms.Results:
OK - The resistance measurement is less than 5 ohms. The harness is correct.Repair: The ECM may have failed. Failure of the ECM is unlikely. Recheck the status of the diagnostic code. If the diagnostic code remains present, exit this procedure and perform this procedure again. If the cause of the diagnostic code is