New Holland ENG 3119 – Engine Control Module (ECM): ECM 12V Sensor Supply Voltage Low

The Engine Control Module (ECM) has detected that the 12-volt reference circuit, which supplies power to various engine sensors, has dropped below the acceptable lower limit.

• T7 Series
• T8 Series
• B110B
• B115B
• B95B
• CR9040
• CR9060
• CR9080
• CX8080
• CX8090
• D85B
• D95B
• D150B
• Magnum 235–340 Series
• 580 Super N
• 1150K/1650L dozers

1. 1

   Verify if the ECU power failed while the engine was running or if the engine shutdown process was incorrect (a known trigger for this code)

2. 2

   Inspect the 12V sensor supply wiring harness for chafing, pinched wires, or direct short circuits to ground

3. 3

   Disconnect the 12V sensors on the engine one by one to isolate any internally shorted sensors pulling the voltage down

4. 4

   Check for a defective ambient pressure sensor inside the ECU

1. 1

   Clear fault code and cycle power

   Clear the fault code and cycle the machine's power using the correct shutdown procedure to rule out a transient power failure glitch.

2. 2

   Test 12V reference pins

   If the code remains active, use a multimeter to test the 12V reference pins at the ECM harness connector.

3. 3

   Inspect engine wiring harness

   Visually and electrically inspect the engine wiring harness. Repair or replace any damaged, melted, or exposed wires causing a short to ground.

4. 4

   Replace shorted sensor

   If a specific sensor was identified as shorted during the diagnostic isolation test, replace that sensor.

5. 5

   Diagnose internal ECM sensor

   If the wiring harness and all external sensors are in good condition, the fault is likely a defective ambient pressure sensor inside the ECM.

6. 6

   Replace ECM

   Replace the ECU if the internal sensor is defective. Note: replacing the ECU is not necessary if never running in high altitude and if turbocharger without VGT.