Case IH 14015 – ICU (Instrument Cluster Unit / ADIC) or Engine Control Module (ECM): Vref_1 or Vref_2 voltage too high

The controller is detecting that the voltage on the Vref_1 or Vref_2 circuit has exceeded the maximum allowable threshold (typically > 5.5V to 6.0V). This is almost always caused by the 5V reference wire shorting to a 12V power source, a sensor failing internally, or a failure of the internal voltage regulator inside the control module.

• Puma/Mid Range Magnum
• Maxxum
• Farmall
• MAXXUM T4E
• Case IH Magnum Series
• Case IH Puma Series
• Case IH Steiger Series
• Case IH Farmall Series

1. 1

   Check System Voltage: Verify the alternator is not overcharging the system. System voltage above 16.5V can cause reference voltage spikes.

2. 2

   The 'Unplug' Test (Isolating the Short): Turn the key ON (engine off). Monitor the Vref voltage with a multimeter at any accessible 3-wire sensor on that circuit. Unplug sensors on the Vref circuit one by one. If the voltage suddenly drops back down to a normal ~5.0V when a specific sensor is unplugged, that sensor is internally shorted.

3. 3

   Harness Inspection: If unplugging all sensors does not resolve the high voltage, inspect the wiring harness for chafing, pinching, or rodent damage. Look specifically for places where the 5V reference wire might be rubbing against a 12V supply wire.

4. 4

   ECU Internal Check: Disconnect the main harness from the ECU. Turn the key ON and probe the Vref output pin directly at the ECU. If the ECU is outputting > 5.5V with nothing connected to it, the ECU's internal voltage regulator has failed.

1. 1

   Disconnect Power

   Turn off the ignition and disconnect the negative battery cable before performing any electrical repairs.

2. 2

   Sensor Replacement

   If the unplug test isolated a faulty sensor (commonly the foot throttle potentiometer or intake air temp sensor), remove the mounting hardware, replace the sensor, and plug the connector back in.

3. 3

   Wiring Repair

   If a short to 12V was found in the harness, carefully open the wire loom. Cut out the melted or exposed section of the wire. Solder a new piece of wire in its place and seal it with marine-grade (adhesive-lined) heat shrink tubing. Re-loom the harness.

4. 4

   Module Replacement

   If the ECU/ICU is outputting excessive voltage internally, the module must be replaced. This will require a Case IH dealer to program the new module using the CNH Electronic Service Tool (EST).

5. 5

   Clear Codes and Test

   Reconnect the battery, turn the key ON, and use a diagnostic scanner to clear the 14015 fault code. Operate the throttle and check sensor data to ensure the Vref stays at a steady 5.0V.