New Holland NH 3118 – Engine Control Module (ECM) / Engine ECU: Power supply for sensors - NOT PLAUSIBLE

This code indicates that the 12-volt supply circuit provided by the Engine Control Module (ECM) to power various engine sensors is reading above the acceptable upper limit, or the voltage reading is illogical. This plausibility error is frequently triggered if the ECU power fails while the engine is running, or if the engine shutdown process was incorrect.

• T6 Series
• T7 Series
• T8 Series
• T9 Series
• Boomer Series
• TM Series
• CR Series
• CR9040
• CR9060
• CR9080
• CR9090
• CX Series
• B110B
• B115B
• B95B
• L218
• L220
• D-Series Crawler Dozers

1. 1

   Verify if the machine was stalled, shut off via a battery disconnect switch while running, or experienced a sudden power loss (improper shutdown cause).

2. 2

   Check the battery voltage and the alternator output to ensure the alternator is not overcharging.

3. 3

   Inspect the ECM wiring harness for chafing, melted insulation, or pinched wires, and use a multimeter to check the 12V sensor supply circuit for a short to battery voltage.

4. 4

   Disconnect the 12V engine sensors one by one to isolate any internally shorted sensor feeding voltage back into the supply line.

5. 5

   Inspect the ECM connectors for corrosion, moisture ingress, or bent pins that could be bridging the 12V supply pin to a higher voltage source.

1. 1

   Clear and Retest

   If the code was caused by an improper shutdown, clear the fault code using a diagnostic tool. Run the engine and perform a normal key-off shutdown sequence. If the code does not return, no further repair is needed.

2. 2

   Repair Wiring Shorts

   If a short to battery voltage is found in the 12V sensor harness during diagnostic testing, locate the damaged section of the harness and splice in new wiring using weather-sealed connectors.

3. 3

   Replace Faulty Sensors

   If disconnecting a specific sensor normalized the circuit voltage, replace that internally shorted sensor.

4. 4

   Replace/Remanufacture the ECM

   If the battery voltage is normal, the wiring harness is intact with no shorts, and all sensors test good, the ECM itself has an internal fault on the 12V supply driver. The ECM must be replaced or sent out for remanufacturing.