Case IH 2173 (518847.03) - DEC – DEC: 12VF failed high

The fault code indicates a 'failed high' condition on the '12VF' circuit, meaning the 12V supply circuit (likely tied to the engine/emissions harness) is experiencing a voltage that is too high or is shorted to another power source.

• MAXXUM T4E
• VESTRUM CVX
• Magnum Tractors (models 235, 260, 290, 315, 340, 370)
• MX/TG Series

1. 1

   Check the condition of Fuse 14, which is associated with the +12VF circuit.

2. 2

   Inspect the wiring and supply voltage for the +12VF circuit to ensure it is not shorted to a high voltage source.

3. 3

   Check the presence, correct connection, and wiring of the Upstream NOx Sensor, as SPN 518847 is associated with the upstream NOx sensor network.

4. 4

   Check the correct functioning of the CAN controller and the CAN configuration in the upstream NOx sensor.

1. 1

   Locate short circuit

   Locate the short-to-high voltage in the +12VF circuit wiring harness.

2. 2

   Repair wiring

   Repair any chafed or melted wires that are bridging the 12VF circuit to another power source.

3. 3

   Replace fuse

   Replace blown fuses (such as Fuse 14) if the short caused a circuit overload.

4. 4

   Replace sensor or module

   If the wiring is intact, replace the affected sensor (such as the Upstream NOx sensor) or module if it has failed internally and is causing the high voltage reading.