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| Illustration 1 | g00841253 |
Schematic for Sensor Supply Voltage | |
The diagnostic code is recorded when the power train electronic control module (ECM) indicates that the voltage of the sensor supply circuit is too low.
Possible causes of this diagnostic code are listed:
- The output of sensor supply has an open circuit.
- The torque converter speed sensor is faulty or the transmission oil temperature is faulty.
System Response:
The machine response is listed:
- The lockup clutch is disabled.
- Hesitation during direction shifts.
- Calibrations will not function.
Test Step 1. CHECK THE VOLTAGE AT THE ECM.
- Turn the disconnect switch and the key start switch to the ON position.
- Check the voltage at the ECM connector from contact J2-12 (sensor supply) to contact J1-16 (ground) or contact J2-9 (sensor supply) to contact J1-15 (ground). Use the 7X-1710 Cable probes to measure the voltage. Do NOT disconnect the machine harness from the ECM.
Expected Result:
The voltage is 8.0 ± 0.5 DCV or the voltage is 10.0 ± 0.5 DCV.
Results:
- OK - The voltage is 8.0 or ± 0.5 DCV or the voltage is 10.0 ± 0.5 DCV. The sensor supply voltage is correct. Verify that the diagnostic code is present. If the diagnostic code is still present the ECM has failed.
Repair: It is unlikely that the ECM has failed. Exit this procedure and perform this procedure again. Also, recheck if the diagnostic code is active. If the cause of the diagnostic code is not found, replace the ECM. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace".
Stop.
- NOT OK - Voltage is NOT 8.0 ± 0.5 DCV or the voltage is 10.0 ± 0.5 DCV. The voltage is less than 8.0 ± 0.5 DCV or the voltage is 10.0 ± 0.5 DCV. The sensor supply voltage is NOT correct. Proceed to test step 2.
Test Step 2. CHECK FOR A SHORT TO GROUND.
- Turn the key start switch and the disconnect switch to the OFF position.
- Disconnect the machine harness from the ECM.
- At the harness connector for the ECM, measure the resistance between frame ground and contact J2-12 and J2-9 of the sensor supply circuit.
Expected Result:
The resistance is greater than 5000 ohms.
Results:
- OK - The resistance is greater than 5000 ohms. The harness circuit resistance is correct. The ECM has failed.
Repair: It is unlikely that the ECM has failed. Exit this procedure and perform this procedure again. Also, recheck if the diagnostic code is active. If the cause of the diagnostic code is not found, replace the ECM. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace".
Stop.
- NOT OK - The resistance is less than 5000 ohms. The machine harness or a sensor has failed. Proceed to test step 3.
Test Step 3. DISCONNECT THE SENSORS.
- The key start switch and the disconnect switch remain in the OFF position.
- One at a time, disconnect any sensor that uses the sensor supply voltage from the machine harness.
- After disconnecting the sensor (s), check the resistance from frame ground to contact J2-12 and J2-9 (sensor supply) of the machine harness connector for the ECM.
Expected Result:
The resistance is greater than 5000 ohms.
Results:
- OK - The resistance is greater than 5000 ohms. The harness circuit resistance is correct. The sensor that was just disconnected has failed.
Repair: Replace the sensor.
Stop.
- NOT OK - The resistance is less than 5000 ohms. If the resistance is less than 5000 ohms after all the sensors have been disconnected from the machine harness. The machine harness is shorted to ground.
Repair: Repair the machine harness or replace the machine harness.
Stop.