Note: There are no diagnostic codes for the 10 volt supply circuit due to hardware limitations. A diagnostic code for the 8V power supply can indicate an issue with the 10V power supply. Verify that there are no issues with the 10V power supply circuit prior to troubleshooting the 8V power supply circuit.
Illustration 1 | g01974433 |
Schematic of the sensor power supply for "7HR" machines |
Illustration 2 | g01974474 |
Schematic of the sensor power supply for "1JW" machines |
Illustration 3 | g01974475 |
Schematic of the sensor power supply for "AMP" and "ADZ" machines |
Illustration 4 | g01974476 |
Schematic of the sensor power supply for "A4W" and "AZX" machines |
This diagnostic code is recorded when the ECM reads the voltage of the 8.0 V sensor supply circuit and the voltage is below normal.
Clear all of the other diagnostic codes before performing the procedure for this diagnostic code. A sensor that has failed in the circuit will cause a diagnostic code for the sensor and for the circuit.
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 machine harness connectors of the ECM from the contact for the 8.0 V sensor supply to the ground contact. 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.
Results:
- OK - The voltage is 8.0 ± 0.5 DCV. The 8.0 V sensor supply voltage is correct. Verify that the diagnostic code is present. If the diagnostic code is still present the ECM may have 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. Refer to Testing and Adjusting, SENR1347, "Electronic Control Module (ECM) - Replace".
STOP
- NOT OK - Voltage is NOT 8.0 ± 0.5 DCV. The voltage is less than 8.0 ± 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 J1 and J2 machine harnesses from the ECM.
- At the harness connector for the ECM, measure the resistance between a clean source of frame ground and the ground contact of the circuit for the sensor.
Expected Result:
The resistance is greater than 5 ohms.
Results:
- OK - The resistance is greater than 5 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. Refer to Testing and Adjusting, SENR1347, "Electronic Control Module (ECM) - Replace".
STOP
- NOT OK - The resistance is less than 5 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 of the machine harness connector at the ECM from a clean source of frame ground to the contact for the 8.0 V sensor supply.
Expected Result:
The resistance is greater than 5 ohms.
Results:
- OK - The resistance is greater than 5 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 5 ohms. If the resistance is less than 5 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